Changed the trans fluid, but a little perplexed

I changed my transmission fluid this afternoon and everything went as it should. No leaks and it shifts great, but what I'm unsure about is the fluid level. According to the manual it takes 2.1 qts but I had to put in over 2.5 for it to register full when "cool". Okay. However when I came back from test driving it 10-15 minutes and checked the level it was still in the "cool" range. I checked it while the engine was off, then with it running, and it didn't show in the "hot" range. This doesn't seem right to me. Am I wrong?

And before anyone gets cute, yes I did put the drain plug back in.

 

Can't speak to autos, but that does sound odd. But you may just need to drive longer to really expand the fluid.

On 5-speeds we just stick our finger in the filler hole, and if it comes out oily, you're set. I actually didn't intend to PUN that

 

Thanks dmac.

Update: The manual says 2.1 but apparently it takes at least four. Mine took almost five qts to show full hot with the engine running.