What kind of quail? (coturnix, bobwhite)
You can NOT trust the thermometer/hygrometer that comes with the incubator. You need to have a tested one that you know is accurate... If you have another thermometer stick it inside the incubator and see what it reads.
I've never float tested. Honestly removing the eggs from the incubator during lockdown is not a best practice. You should candle at day 14 (lockdown for coturnix) and throw away any clears. Then raise the humidity, shut off the turners, and do not open the incubator until the majority have hatched.
Also the day you set them is day 0 not day 1. So if I set them at lunch on Monday, Tuesday is day one. Mine typically pip day 17 and start hatching late day 17 and all day on day 18. I have had a couple stragglers early day 19 but not very often. I personally have not had any issues hatching shipped quail eggs....