Hi Nicholas
you can easily double check on the mergedogmonitor process by displaying it in the Administration Console -> Performance -> Threads.
Make sure the filter settings include mergedogmonitor and that the <active> filter is disabled.
You'll see something like this then:
Apart from that, I believe the threshold function will simply not indicate a merge for your tables.
You may look into the mergedogmonitor trace (trace level INFO) to get a report on the evaluation.
- Lasr