ls swap, 4l80e acting funny

[Lookin4the1]

Current setup:
6.0 LS with a bigger cam and springs.
4l80e with circle d 3200 stall converter

I didn't go through the transmission when I got it. I was told it ran well and shifted fine. During my first few test drives it just seems like the trans wants to shift to 4th and overdrive wayyyyy too quickly. I bought the computer separately and will have to get it tuned. It was in another swap before mine. I'm just starting to freak out about getting this transmission rebuilt.

my question is:

while tuning ( I know nothing about tuning) can the tuner adjust the trans control to pick different shift points? I'm assuming tire height and rear end gearing has a lot to do with it.

Or

Is this a serious problem that I should go ahead and fix before throwing more time and money on different parts of the project. I'm 95% complete