TCC lockup temperature

Working on a car I did a while ago. Owner says that some days it does not lock up the torque converter until after he has driven it for an extended period of time. Other days, it locks up just like it should within the first mile or two. With it getting colder, could it be just that the transmission temperature is taking longer to warm up? I know on the Allison transmissions, TCC won't lock in until after the temperature reaches a certain value. Do the 4Lxx transmissions also do the same? I didn't see any tables (values) in the software that point to something that we can change. Maybe there is something else going on? For reference: it has a built transmission and it still rips the shifts off like it should :).

It is temperature dependent (even tho there are no tables exposed)...

one of the TSTATE pid's shows reason why TCC is unlocked.

Do you know what the temperature is? Or if there is a CAX file to make any changes?

The temperature is stated in the GM Service Manual per vehicle model...

I can lookup most models upto 2005.