Hi,
Did you ever figure out what was causing your low speed shift problem? Mine does pretty much the same thing as what you described. If I accelerate, slow down and then accelerate again like in stop and go traffic, sometimes the engine rpm's will go way up and then it jumps into 1st gear again. Almost as if it went into neutral for a few sec's and then back into gear. Like the engine is having to catch back up with the transmisstion. It's pretty odd I think. I don't really remember it doing that until the last fluid change was done. Toyota IV fluid was used. I also notice a slight rpm flare say around 100 rpm or so between 1st and 2nd. I don't remember it doing that either. It actually shifts too smooth for my liking. I like to at least feel something between gears.
Thanks,
Jason