i swear im losing my mind with this 4l80e fluid

[Murdered_GMC]

hey guys i have a 2004 sierra 2500 6.0 4l80e. now im having an issue that i dont understand at all. so before i say anything the truck drivers perfectly fine shifts fine doesn't get hot no burnt fluid smell fluid is still red as can be. so my issue i swear every time i check the fluid level its different. last summer i checked it and it was reading pretty low but still on the stick so i put about a half quart in nothing crazy. i drove all winter fine then into this summer. i checked it again a couple months ago and it was the same low but still reading on the stick. so i added about a half quart like last time and it was good. now fast forward to last month i checked it after riding around on a 90 degree day trans was about ehh 175 180ish degrees and it read literally perfect on the stick so i was like ok cool. so now then last week i checked it and it was low but still on the stick so im like uhhhhhhh. so today i checked it again its a little colder here like 55 and the trans was about 150. i pulled the stick and it was same spot low but on the stick so im like ok ill check it when i get home. so i get home check it and now it is reading above the cold mark but just below the first HOT marker hole. prob like .25 of a quart low honestly. so my question is i looked in the manual and it says to check the fluid at 180-200 degrees because thats the operating temp. now with it being 55 out today and the trans about 140-150 would it make that difference of reading just under the first HOT marker hole. also im pretty sure the truck probably does have an extremely slow leak i did get under it and noticed on the trans cross member bolts one of them has a little fluid on it but nothing crazy its not even enough to drip honestly. so my question is does the trans NEED to be 180-200 degrees to check it? like will it always read low if its not at 180-200? also forgot to mention i know how to check the fluid ive done it a thousand times i drive it around warm it up bring it back park it on the level surface of my driveway shift threw all the gears waiting about 4-5 seconds between then put it back in park pull the stick wipe it and check it. i also try to not check it after driving on the highway ect i always check it after driving around town or riding up and down back roads. thanks guys!