diff --git a/src/cases/report_timing.cpp b/src/cases/report_timing.cpp
index 4e772a23..ce499c77 100644
--- a/src/cases/report_timing.cpp
+++ b/src/cases/report_timing.cpp
@@ -88,7 +88,8 @@ int print_timing_WR(e3sm_io_config *cfg,
              + decom->max_nreqs[i] * sizeof(int); /* D*.lengths */
         sum_decomp_varlen += vlen;
     }
-    sum_decomp_varlen *= cfg->sub_nprocs;
+    if (cfg->sub_comm != MPI_COMM_NULL)
+        sum_decomp_varlen *= cfg->sub_nprocs;
     if (cfg->strategy == blob && cfg->api != adios && cfg->sub_rank > 0)
         sum_decomp_varlen = 0;
     /* sum_decomp_varlen is the size of all decomposition variables defined in
diff --git a/src/e3sm_io.c b/src/e3sm_io.c
index 729f9daa..496a1896 100644
--- a/src/e3sm_io.c
+++ b/src/e3sm_io.c
@@ -275,6 +275,7 @@ int main (int argc, char **argv) {
         decom.disps[i]       = NULL;
         decom.raw_offsets[i] = NULL;
         decom.w_starts[i]    = NULL;
+        decom.max_nreqs[i]   = 0;
     }
     ffreq = 1;