diff --git a/Gemfile b/Gemfile
index 1fe2fde746..ac31d89773 100644
--- a/Gemfile
+++ b/Gemfile
@@ -117,7 +117,7 @@ group :development do
   gem "ed25519", ">= 1.2", "< 2.0", require: false # Required to support ed25519 SSH keys for capistrano. https://github.com/net-ssh/net-ssh/issues/565
   gem "haml_lint", require: false
   gem "letter_opener"
-  gem "rubocop", "1.73.0", require: false
+  gem "rubocop", "1.73.2", require: false
   gem "rubocop-performance"
   gem "rubocop-rails"
   gem "rubocop-rspec"
diff --git a/Gemfile.lock b/Gemfile.lock
index 92763ded8d..37e55f393d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -138,8 +138,8 @@ GEM
     amazing_print (1.7.2)
     ast (2.4.2)
     aws-eventstream (1.3.1)
-    aws-partitions (1.1056.0)
-    aws-sdk-core (3.219.0)
+    aws-partitions (1.1060.0)
+    aws-sdk-core (3.220.0)
       aws-eventstream (~> 1, >= 1.3.0)
       aws-partitions (~> 1, >= 1.992.0)
       aws-sigv4 (~> 1.9)
@@ -401,7 +401,7 @@ GEM
     mime-types (3.6.0)
       logger
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2025.0220)
+    mime-types-data (3.2025.0304)
     mini_magick (5.2.0)
       benchmark
       logger
@@ -451,7 +451,7 @@ GEM
       activerecord (>= 6.1)
       request_store (~> 1.4)
     parallel (1.26.3)
-    parallel_tests (4.9.1)
+    parallel_tests (5.0.1)
       parallel
     paranoia (3.0.1)
       activerecord (>= 6, < 8.1)
@@ -482,7 +482,7 @@ GEM
     puma (6.6.0)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (2.2.11)
+    rack (2.2.12)
     rack-test (2.2.0)
       rack (>= 1.3)
     rack-utf8_sanitizer (1.10.1)
@@ -560,7 +560,7 @@ GEM
     rspec-support (3.13.2)
     rspec_junit_formatter (0.6.0)
       rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (1.73.0)
+    rubocop (1.73.2)
       json (~> 2.3)
       language_server-protocol (~> 3.17.0.2)
       lint_roller (~> 1.1.0)
@@ -577,7 +577,7 @@ GEM
       lint_roller (~> 1.1)
       rubocop (>= 1.72.1, < 2.0)
       rubocop-ast (>= 1.38.0, < 2.0)
-    rubocop-rails (2.30.2)
+    rubocop-rails (2.30.3)
       activesupport (>= 4.2.0)
       lint_roller (~> 1.1)
       rack (>= 1.1)
@@ -789,7 +789,7 @@ DEPENDENCIES
   rspec-collection_matchers
   rspec-rails
   rspec_junit_formatter
-  rubocop (= 1.73.0)
+  rubocop (= 1.73.2)
   rubocop-performance
   rubocop-rails
   rubocop-rspec
diff --git a/app/controllers/order_management/order_details_controller.rb b/app/controllers/order_management/order_details_controller.rb
index 0698c7968a..d196c86cb1 100644
--- a/app/controllers/order_management/order_details_controller.rb
+++ b/app/controllers/order_management/order_details_controller.rb
@@ -13,7 +13,7 @@ class OrderManagement::OrderDetailsController < ApplicationController
   # We can't load through the facility because of cross-core orders
   before_action :init_order_detail, only: [:files, :template_results]
 
-  helper_method :edit_disabled?
+  helper_method :edit_disabled?, :actual_cost_edit_disabled?
 
   before_action :authorize_order_detail, except: %i(sample_results)
   before_action :load_accounts, only: [:edit, :update]
@@ -117,7 +117,19 @@ def load_order_statuses
   end
 
   def edit_disabled?
-    @order_detail.in_open_journal? || @order_detail.reconciled?
+    in_open_journal_or_reconciled = @order_detail.in_open_journal? || @order_detail.reconciled?
+
+    if SettingsHelper.feature_on?(:allow_global_billing_admin_update_actual_prices)
+      in_open_journal_or_reconciled || (@order_detail.awaiting_payment? && !current_user.global_billing_administrator?)
+    else
+      in_open_journal_or_reconciled
+    end
+  end
+
+  def actual_cost_edit_disabled?
+    return false unless SettingsHelper.feature_on?(:allow_global_billing_admin_update_actual_prices)
+
+    @order_detail.awaiting_payment? && !current_user.global_billing_administrator?
   end
 
   def init_order_detail
diff --git a/app/helpers/products_helper.rb b/app/helpers/products_helper.rb
index 5dce81c48e..ff1ed96b8d 100644
--- a/app/helpers/products_helper.rb
+++ b/app/helpers/products_helper.rb
@@ -20,11 +20,15 @@ def options_for_control_mechanism
   end
 
   def options_for_relay
-    {
-      RelaySynaccessRevA => RelaySynaccessRevA.name,
-      RelaySynaccessRevB => RelaySynaccessRevB.name,
-      RelayDataprobe => RelayDataprobe.name,
-    }
+    [
+      if SettingsHelper.feature_on?(:disable_relay_synaccess_rev_a)
+          nil
+      else
+        [RelaySynaccessRevA, RelaySynaccessRevA.name]
+      end,
+      [RelaySynaccessRevB, RelaySynaccessRevB.name],
+      [RelayDataprobe, RelayDataprobe.name],
+    ].compact
   end
 
   def instrument_pricing_modes
diff --git a/app/services/order_details/param_updater.rb b/app/services/order_details/param_updater.rb
index fbc32b81b2..e14da68833 100644
--- a/app/services/order_details/param_updater.rb
+++ b/app/services/order_details/param_updater.rb
@@ -106,7 +106,13 @@ def assign_price_changed_by_user
   end
 
   def cost_params(params)
-    params.slice(:actual_cost, :actual_subsidy).permit!
+    return params.slice(:actual_cost, :actual_subsidy).permit! unless SettingsHelper.feature_on?(:allow_global_billing_admin_update_actual_prices)
+
+    if !@order_detail.awaiting_payment? || @editing_user.global_billing_administrator?
+      params.slice(:actual_cost, :actual_subsidy).permit!
+    else
+      {}
+    end
   end
 
   def permitted_params(params)
diff --git a/app/views/order_management/order_details/_costs.html.haml b/app/views/order_management/order_details/_costs.html.haml
index a4e4e532fd..b3abdfe385 100644
--- a/app/views/order_management/order_details/_costs.html.haml
+++ b/app/views/order_management/order_details/_costs.html.haml
@@ -1,7 +1,7 @@
 - f.object.send(:extend, PriceDisplayment)
 - if f.object.actual_cost?
   .cost-table
-    .cost= f.input :actual_cost, as: :currency
+    .cost= f.input :actual_cost, as: :currency, disabled: actual_cost_edit_disabled?
     .subsidy=  f.input :actual_subsidy, as: :currency, disabled: !f.object.price_policy.try(:has_subsidy?), hint: "#{f.object.price_policy.try(:price_group)}"
     .total= f.input :actual_total, as: :currency, disabled: true
 - else
diff --git a/config/settings.yml b/config/settings.yml
index 781b69fa5e..9bedb58ac5 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -162,6 +162,8 @@ feature:
   show_daily_rate_option: true
   sanger_enabled_service: <%= ENV.fetch("SANGER_ENABLED_SERVICE", false) %>
   well_plate_alternative_csv_format: <%= ENV.fetch("well_plate_alternative_csv_format", false) %>
+  disable_relay_synaccess_rev_a: false
+  allow_global_billing_admin_update_actual_prices: false
 
 split_accounts:
   # Roles are allowed to create Split Accounts
diff --git a/spec/helpers/products_helper_spec.rb b/spec/helpers/products_helper_spec.rb
new file mode 100644
index 0000000000..b31bdd606c
--- /dev/null
+++ b/spec/helpers/products_helper_spec.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe ProductsHelper do
+  describe "#options_for_relay" do
+    let(:subject) { options_for_relay }
+
+    it(
+      "list all relay types if none disabled",
+      { feature_setting: { disable_relay_synaccess_rev_a: false } }
+    ) do
+      expect(subject.to_h).to include(
+        RelaySynaccessRevA,
+        RelaySynaccessRevB,
+        RelayDataprobe
+      )
+    end
+
+    it(
+      "exclude synaccess rev a if disabled flag is on",
+      { feature_setting: { disable_relay_synaccess_rev_a: true } }
+    ) do
+      expect(subject.to_h).to_not include(RelaySynaccessRevA)
+    end
+  end
+end
diff --git a/spec/system/admin/instrument_relay_tab_spec.rb b/spec/system/admin/instrument_relay_tab_spec.rb
index 901a1992fe..d838c24d77 100644
--- a/spec/system/admin/instrument_relay_tab_spec.rb
+++ b/spec/system/admin/instrument_relay_tab_spec.rb
@@ -2,7 +2,7 @@
 
 require "rails_helper"
 
-RSpec.describe "Instrument Relay Tab" do
+RSpec.describe "Instrument Relay Tab", feature_setting: { disable_relay_synaccess_rev_a: false } do
   let(:facility) { FactoryBot.create(:setup_facility) }
   let(:user) { FactoryBot.create(:user, :administrator) }
 
diff --git a/spec/system/admin/manage_order_detail_spec.rb b/spec/system/admin/manage_order_detail_spec.rb
index 5a702ba7b7..0cccae36b2 100644
--- a/spec/system/admin/manage_order_detail_spec.rb
+++ b/spec/system/admin/manage_order_detail_spec.rb
@@ -363,4 +363,50 @@
       end
     end
   end
+
+  shared_examples "allows to update actual cost" do
+    it "allows to update actual cost" do
+      expect(page).to have_field("order_detail[actual_cost]", disabled: false)
+    end
+  end
+
+  describe "updating actual cost" do
+    let(:statement) { create(:statement, facility:, created_by: 1) }
+
+    before do
+      start_at = Time.zone.parse("#{Date.today} 10:00:00") - 1.day
+      end_at = start_at + 1.hour
+
+      reservation.update!(actual_start_at: start_at, actual_end_at: end_at)
+      order_detail.update!(reviewed_at: 5.days.ago, statement:, actual_cost: 10)
+
+      visit manage_facility_order_order_detail_path(facility, order, order_detail)
+    end
+
+    context "with feature flag ON", feature_setting: { allow_global_billing_admin_update_actual_prices: true } do
+      context "as a global admin" do
+        it "does not allow to update actual cost" do
+          expect(page).to have_field("order_detail[actual_cost]", disabled: true)
+        end
+      end
+
+      context "as a global billing admin" do
+        let(:logged_in_user) { create(:user, :global_billing_administrator) }
+
+        it_behaves_like "allows to update actual cost"
+      end
+    end
+
+    context "with feature flag OFF", feature_setting: { allow_global_billing_admin_update_actual_prices: false } do
+      context "as a global admin" do
+        it_behaves_like "allows to update actual cost"
+      end
+
+      context "as a global billing admin" do
+        let(:logged_in_user) { create(:user, :global_billing_administrator) }
+
+        it_behaves_like "allows to update actual cost"
+      end
+    end
+  end
 end