Transmission overdrive slipping

Currently with the car at operating temperature, on level surface, in park, checking the trans dipstick shows that the level is in between the hash mark, not too low, not 100% full though. The fluid is still lightly pinkish brown, no dark colors. No check engine light, would I code still be able to be present without a check engine light? Attached photo is from car care kiosk just to show you the level at which my 626 is at. Should it be topped off? Should I use something like Lucas oil trans fix to top it off?

I really have been freaking out over this as this is the last car out of 3 that was running correctly, the one I own. I have 2 roommates who also work and are now using my darn car to get around and now this is happening making 45 roads unable to be driven on. Which is most roads. It's nice to just be able to lay out my options of what to do so let me just say, thank you.

Update: the night before last I took the 626 on the street and drove it for a decent chunk of time, about 20 miles at 45. And I got 0 issues with the transmission, it was flawless. But after about 20 miles it started back up again. This made me think it was a heat issue maybe combined with the bad fluid, and I realized my cooling fan isn't running at all even though I have no overheat on the engine temp gauge, directly in the middle like normal for the heat. So I went to bed with a plan to replace the cooling fan and change the fluid. I went to advance auto, and when I was leaving I started the car and revved to almost 3.5k and it popped up a check engine light p0708. I immediately shut it off and took it to an express oil to have the check it out. I was told the transmission range sensor is bad and it would need replaced. I then mentioned that it was the first time it's happened, and he had the mechanic clear the code and take it for a test drive. He drove it for 15 miles in the florid heat with no issues. I drove it home with no issues. I do know what to do, the owner of the shop recommended just topping off the transmission with Lucas oil he said about a pint or slightly less.

Send me the diag procedure and I'll see if I can do it. I'm worried with the shitty rep this transmission model has that it may just be slowly dying as it's worn out at 110,000.

Just wanted to give an update on this. Sorry it's so late, got a lot going on but good news is it's fixed. P0708 led me to search up very detailed about the 626. It was a faulty neutral safety switch sending wrong info to the TCM when hot. The sensors degrade over the years and then when they get hot it will cause the issue with a bad sensor. I replaced the sensor for about $22.00 and haven't had an issue.