I have also noticed these strange issues. Although there is a constant high hashrate on the console, I see there is lot of variance on the pool site hashrate and they are lower. Sometimes for a short period it peaks and is increased but, for a short period. This was observed consistently across several pools. I have been using Bminer for a while however, with these observations and the dev not really addressing the issue that is a concern.

I will be returning back to the more obvious and consistent DSTM.