It might not be a good idea in a highly stressed racing engine, but should be OK in any normal application. I can't imagine it doing anything more than warping the oil pan and creating a slight leak. This assumes that you are adding 1-2 quarts for top-off. When changing the oil, the obvious assumption is that you drained the old oil first, which allows the engine to cool off some before you dump in a large quantity.

PT6's most accurate oil level is when it is checked within 10 minutes of shutdown.

I'm guessing Jungle owns a C310-R. I love those planes(only flew 2000 hrs in them at my last job). You actually own a FIKI model, or 'full-deice?' I'm suprised the 9 quarts was too much, in our fleet(9 R-models) we'd usually go around 9-10qts and be fine.

As far as any engine in general, I believe whatever its "Max" value is, is the engine can usually run on 50% of that for certification purposes. Funny how it all works in the end.

How I usually manage oil levels, I usually fill for normal 1-3hr flight 75% of the max level, and I'll go +1 qt. for longer flights just to cover myself if I don't know that specific aircraft.

the company I fly for has several different models of citations.... and they all suggest the oil be checked within 10 minutes of shutdown. Usually add a quart when the engine indicated 1.5 quarts below max.

With regard to the oil reading changing with regards to shutdown time, and temperature. I was always taught and I teach my students that if the engine has been run within the past 30 minutes then the reading may be low by up to 1/2 a quart not because the oil is still hot but because some is still in other parts of the engine. I also teach them if its below what the book says is the min then get it at least 1/2 quart over the min. Anybody else teach or been taught this? I never knew about the half oil certification level but that makes me feel alot better, but im not going to tell my students because I don't want them to think they can go out with less then recommended. :D

Hot oil runs very quickly. On a piston engine, after 5 minutes it should all be in the sump except for a thin film on the parts which does not contain enough oil to affect the dipstick level.