What both places were telling you was the "initial fill" that their
reference book called for. It sounds like the first place had the right
figure. Now that you know how much fluid the initial fill should be it might
be a good idea to write it down somewhere.

The initial fill is how much fluid you should put in it before trying to
warm it up. You shouldn't try to get the transmission up to operating
temperature when it's extremely low on fluid, and you can't check the level
unless it's warm. So what do you do? Dump the initial fill amount in it and
warm it up. Then, with the engine running and parked on a level surface, run
it through all the gear positions, put it in neutral, and top it off as
needed.
When you think you have the fluid at the right level, drive it for a few
days and check it again. I always find them to be a bit low a few days
later.