I have one of those little air compressors that you plug into a car's cigarette lighter. I keep having a problem. When it reaches the proper tire pressure I lose a lot of air just removing the nozzle from the tire. I try to do it as quickly as I can, but it drops 10 or 15 lbs when I do it. Should I just overinflate to compensate, so that when I remove the nozzle it is correct?

Remove the pump-nozzle faster!

What happens is when you unflip the lever to remove it, you end up cocking the nozzle sideways and cause it to bind on the valve-cap threads. Then you can't pull it off quickly and the air leaks out. You need to separate the lever-flip motion from the pull-off motion, which has to be on the same direction as the axis of the valve-stem itself.

To do that, use two hands. Put the index finger and thumb of one hand on the valve-stem between the pump-nozzle and rim (wrapped around the valve-stem). These two fingers' function is to slide up the valve-stem and push off the pump-nozzle.

Use the other hand to unflip the lever on the nozzle. Best to position yourself so that the lever is aimed away from you. Then use your thumb to reach over the lever and pull it up towards you to unlock. At the same time, use the knuckles of your index finger to push in the opposite direction on the nozzle-body. This counteracts the rotation imparted by the thumb to unlock the lever. This keeps the nozzle as steady as possible with the only movement being to unflip the lever.

At the same time as you're locking the lever with one hand, slide the other hand's fingers up the valve-stem and push off the nozzle. Pffft, quick release and ejection of the nozzle with little air-loss...