There's a bug in the papi_cost utility that grossly under-reports the start/stop times for PAPI execution.
To fix it, download the new source from: papi/utils/cost.c and rebuild.
This bug was introduced between the PAPI 3.6.0 and 3.6.1 releases and affects results in PAPI 3.6.1 and 3.6.2 installations. It is not a bug in PAPI itself; only in the utility.
Thanks to Rick Kufrin of NCSA for identifying and reporting this bug.