Update. I haven't done any treatment other then the one sugar dusting of the colony and some drone removal (2 weeks in a row) and today's sugar roll revealed only 3 mites.
I have read that hygenic behavior may not kick in til the weather warms. I don't know if it was the sugar roll combined with drone removal or the weather warming or the replacement of the oil in the pans but. The hive had no beetles I saw and the mite count is way down.
Pretty happy with that. I'll keep monitoring the mites but back to not treating or manipulating this hive for mites. Will still manage to stop swarms and such.