I go one step further……..I drain the vehicle cold after sitting overnight with the Fluid jugs sitting next to the vehicle so both fluids ambient temperatures are equal.So the volume doesn't change. If you drain hot and measure hot, and put the same amount of cold fluid in, you will be putting in more.
You can drain a gallon hot and watch it shrink as it cools.
Excessive, maybe…….it’s just what I do!