I am finishing my basement, and have primed and painted the drywall ceiling with SW drywall primer and ceiling paint. After I was done, I noticed a couple of screw holes that I missed while finishing the drywall. After patching with compound, and hitting with primer, I noticed that I ran out of ceiling paint. However, I have a 5 gallon bucket of SW flat white left from another project. This would be more than enough to do the entire ceiling (4 times). Can this be used? Is there anything in ceiling paint that makes it special flat white?
Ceiling paint has a little different formula to make it more splatter resistant and most won't be a pure white when they dry. They have a hint of grey in them to make the ceiling not stand out as much, which is kinda what you want. However I have done plenty of ceilings with just a flat white end even some strange colors, so there is no reason why you can't use the flat white you have on the ceiling, it just may drip a bit more. No biggy.
IIRC, "Ceiling White" has just a hint of blue in it. (I can't remember why.) And yes, it is more spatter resistant. However, unless you are a painting contractor hauling ass, I can't imagine this is a big problem.
I use dead flat in SW stock Extra White, and it looks just fine. I used to use Classic99, and then switched to ProMar 200 because it came in a fiver for less money.