What you need to keep in mind when you treat is that the queen gets hit every time you apply it. The workers die off in 6 weeks so they won't see multiple treatment regimens. I know of many people who use OAV who remove the queen when they perform the vaporization and place her back in 10-15 minutes later. This prevents the queen from getting nailed with treatment after treatment. The commercial guys I know treat like crazy and while their winter losses are very low, they do requeen every year.