Not a dumb question at all!

The MAIN "Aegis"-like point here is...
"There's no such thing as a perfect match."

It's just not possible. I can get D@MN close usually, given some time to tweak a color. Unless you're using "company X's" formula and colorants...100% isn't possible. Won't happen.

Do this:
* Buy a Qt. of the colormatch at your PPG store. Give the staff some time to tweak it.
* Have them save the "final" Qt. formula.
* THEN...brush/roll some out...onto foamboard samples. Do 2 coats, just as you would on the actual wall.

>>> DON'T brush samples onto the wall!!

* Now let it dry a few hours, and check the appearance the next day.
* Move your samples around the room, and check in different lights. Use painter's-tape and put-'em-up for a while!
* If you're satisfied, have them scale-up the formula to a gallon.

Faron