transmission observation

I was rushing to change my oil before a trip across the state this weekend and made an amateur hour error by pulling my transmission drain plug instead of the oil pan plug (don't ask- it was stupid and I've already kicked myself a number of times for the goof).

So it occurred to me as while it was draining T fluid and my headlamp went out and I stuck my finger in the hole (that's what she said!) and stopped the flow and wrestled the bolt back in. I had no clue how much had drained, but guessed near 2 quarts. I went ahead and properly changed the ENGINE oil then, and had the missus take me to pick up some Trans fluid. So I got to the parts store and found that there is little that is compatible with the Toyota WS fluid but that Havoline Xtra somethingorother is. So I grab a couple quarts, get home and read on how to add the right amount- find it here on the site and it's simple enough to short the OBD to get into transmission diagnostics. Anyway, I got to the thin stream flowing out of the overflow hole and torque everything back down. and now I get tot he point of the thread----

--- my shifts are better than ever. The way the transmission downshifted when getting heavy on the gas- heck, even getting on the gas, it seemed like the trans would go from drive to 2nd gear instead of only dropping one gear. Now, after my bungle, the unintended consequence of my mistake is that I have control over the shifts with the gas pedal, the shudder that was there when the trans shifted from 4th to D under load is gone.

some guys said that their trans seemed better after changing to the Havoline. I didn't change, and only added 1.6 quarts back, but it's clearly different now.

Have ya'll changed your trans fluid? Flushed or just drain and replace? Supposedly, the T holds around 12 quarts, but the drain and replace only changes around 5 quarts of it.

My old 4runner has 360K on it and at 300K, the trans fluid looked near new.