Getting precharged tank pressure exact

[tropics surfer]

Hello again, I have a Dayton 3GVT9 62 gallon vertical tank and have had no problems with it, but lately I notice when the water chamber is near empty the pressure drops noticeably.
I bought a second air pressure gauge which has added to the issue. I've been running the pressure switch at 32-52 psi for some time now and my older pencil type gauge shows 30 psi while the new screw on gauge shows 33 psi. I wonder which one is correct?
With the low pressure at the end of the cycle, what do you think?

 

[Valveman]

Too much air in the tank will cause a momentary hesitation in the water supply as the gauge quickly drops from 30-33 to zero before the pump starts. As soon as the pump starts it will quickly bounce back to 30-33 and start climbing again. It is better to have a little less air in the tank than to have too much.