@tommy dave, I'm here. We are more than comfortable discussing Bayvarol with NZ Beekeepers. Sorry I haven't posted recently. I have been busy working hard on resupply of Bayvarol.
I can't speculate about the reasons why some mites are been seen in hives treated with Bayvarol. @frazzledfozzle is right, 4 strips per hive should do the job. It takes time for the active ingredient on the strips to spread around all the bees and any varroa in the brood cells won't be exposed to the active u
Official procedure for reporting issues with Bayvarol.