1st time kegging - understanding temperature / pressure

I am getting ready to go for it with my first draft system in cornelius kegs. I have read a lot, probably too much about draft systems and am only slightly more confused now than when I started!

In any case, I understand about using a carbonation table with temperature vs. pressure. My question is: I presume that these charts assume your beer is already at the temperature, say 40F, to use with 10psi. What about if your beer has been at 60F and you don't have the option to "crash cool' it before kegging? What PSI would you use in this case if, once you do keg it, you then cool it to 40F? If you charge it at 20PSI and then place the keg in a 40F fridge for 2 weeks, will it reach the correct equilibrium, or will it be overcarbonated, and you should have used 10PSI to begin with?

No I can't crash cool straight from the fermenter, so please don't suggest that.
Cheers,
Roberto

Those temperatures aren't crash cooling temperatures. They are serving temperatures.

To find the temperature you are serving at, measure the second pour into a room temperature glass with a calibrated thermometer and set your co2 to match based on your chart or table.

Edit: And look into the set it and forget it force carbing method. Makes it very easy.

I would put it this way -
The carbonation chart tells you what pressure you need for the temperature the beer is at. If the beer is 60 and will be at 60 while it carbs, that's where you set the pressure. If the beer is room temperature, but you throw it in the cooler and put gas on it, set the pressure for the temperature it will be at in the cooler.

If you set it for 20 PSI and put it in the cooler for a week, you'll have over-carb'd beer...

Understood