hummm ... I don't know what to say on this one.
With female underarms, I guarantee (yes a real guarantee) that the entire job will take no more than 8-hours (total). If it does, treatments are free. (It's all about HOURS ... not "years.")
This is MY standard ONLY, and no one else should state this ... They should, however, be able to state their own averages (for non-hormonal body hair such as underarms).
If your blend person is taking "too long" (10-seconds is fine) maybe this time the hairs will be killed ... thus making the "too long" actually quicker.