The test wt_operation_stats.js looks for the storage statistics in the profiled output of the find operation. The find operation in the test is executed in two parts 1. find command itself and 2. getMore triggered by the find. The test always looks for the storage statistic in the last profiled command (getMore in this case). getMore does not always have the storage stats. It is the find command that always has the storage stats. Hence look for storage stats in the find command's profiled entry.