Why has my cold transmission fluid level changed on the dip stick?

[69GTX]

Strange one. For the previous 6 yrs on my 2001 Lincoln (AX4N FWD) with 74K miles always had repeatable readings on the stick
both when running (park, idle, hot) as well as when engine off & cold (level at the top of letters "ss" on the stick). Of course
the cold level is higher on the stick. My dip stick is stamped "do not fill if above the cross hatched area"). Shortly after beginning
transmission fluid changes on my Lincolns I discovered that COLD levels were indeed perfectly repeatable. Never varied. Until now.

So after my recent 14 qt flush from 1-2 weeks ago (pan not serviced) I was very careful to leave myself 1/2 to 1 quart to play with.
i slowly added that in over several drives when measuring the level HOT. I ended up with level at the top of the cross hatched area
which is about 1/2" wide. But this time around, the cold fill level is now always showing in the middle of "area" on the dip stick....about 5/8" higher than in the past. I'd estimate that's 1/2 quart or less.

I'm still checking the HOT level after every drive to ensure it's not above the normal band on either side of the stick, and that both sides are the same. After 25 yrs with this exact same transmission in 3 diff. 1997-2002 Lincolns, same stick, and hundreds of measurements, I don't think I'm reading the stick wrong. Could it have to do with fluid being fresh now vs. 6 yrs/25K mi old?

Car shifted perfectly both before and after the flush. No performance issues. No leaks on the car, not a drop of anything.

 

[zrxkawboy]

Total speculation here, but maybe the base oil blend of the new fluid is different, so it expands at a slightly different rate, meaning cold vs hot volumes vary a bit.

 

[69GTX]

Total speculation here, but maybe the base oil blend of the new fluid is different, so it expands at a slightly different rate, meaning cold vs hot volumes vary a bit.

That could be possible. Though, I did use the exact same branded fluid (Super Tech Mercon V) last time around too.
A change in their base formulation?

 

[69GTX]

Think I found the problem. The pan is slightly over-filled. Was able to get 4 good readings today in cloudy overcast conditions in 2 different parking lots, each time the stick was the same.....showing 1/8" to 3/16" above the normal operating band. So probably around 4-8 oz of extra fluid in there. I'm surprised that little bit adds another 5/8" total on the dipstick when cold.

I plan on getting a plastic hose and siphoning out a few ounces. Note that there is a factory obstruction in the dip stick tube that prevents you from putting anything down there beyond the top of the pan. But I should be able to get out a few ounces.