So a general question on this topic, it'll be a long one so hold tight.  Disclaimer, I may be assuming and making assumptions please don't beat me up over it I'm just interested in others thoughts.
We treat in Aug to ensure the eggs, larva being born 3 weeks later are free of Mites.  We assume we've got our mite numbers to a minimum, (assume) this holds the mite loads down until a late influx as we're talking about (late season influx via robbing etc...)  This means at this time (time of influx) our bees are healthy and free from disease related to mites.

Mid Oct:We now have an influx of Mites (how many per hive???) and now phoretic mites are feeding on our adult bee's.  
Q:    How much damage and how quickly does this damage effect the adult population??  
At this time most if not all mites should be in a phoretic state due to lack of brood, so we can assume limited if any mite reproduction.I then treat in Nov with dribble (input your choice here) and knock the mite numbers back down.

Q:    What should/would I expect would be the damage to my hive from the 1 month infection to adult population?  
Assume a 10% infection rate to a Hive containing 10K bees.
Q: Is that enough to seriously effect the wintering ability of that hive?  Let's just assume once again adequate feed and everything else is in order.
 I'm asking these question for simple reason.  I've seen the back and forth emails on this subject, if your treating and getting expected efficacy is this influx really something to be concerned with?
  

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