Checked mine cold and hot same mark on stick as when cold and same mark on stick hot. simple science molecule don't get bigger when hot just move faster.
Oils expand as they warm up, what this tells me is either: A) you didn't wait for it to fully drain back before checking hot (full operating temp), B) you burned/leaked the difference, or C) you didn't actually mark the stick accurately enough to truly check.
Formula for oil expansion is: (1+[TxE])xXgal=Ygal
T= temperature differential
E= expansion/°F (.0006/deg F for waste oil fuel)
X= original measurement
Y= Final measurement
So your crankcase starting at 2.5gal at 70°F to an operating temp of 180°F would give us: (1+[110x.0006])x2.5gal= 2.665gal
meaning only minimal changes not massive changes.
I'd consider that a significant change
Now, this is assuming your oil was measured EXACTLY 2.5gal at 70° when it was bottled, and you got every bit out (both rather unlikely). You realistically could have added anywhere from 2.3 to 2.7 gallons when you filled your crankcase due to temperature variances.
Even Porsche has a 1/4" tolerance on their dipstick length to boot, they cover a "safe operating range" from -20°F to operating temp, otherwise you would have one notch saying "This is exactly where your oil level needs to be."
I'll try to remember to take a picture of the shop loader dipstick when I run the checks at work in the morning (1988 Cat 936E) one side has a cold safe starting range which is much lower than the at temperature range on the other side (8.3 gal crankcase).
Aren't math and science fun? I had to learn this when I was making new oil heater storage tanks for an asphalt plant.
They heat oil to a temperature of 600° for their hot oil heaters for the asphalt, so the 1600 gallon capacity tanks were built with a true capacity of 2300 gallons to prevent boil-over.
Mineral oil expands at a rate of .00036/°F.
Crude oil expands at a rate of .00069/°F due to Benzene content.