We do the performance calculations ourselves and put the data in the box. Why would we want to have a central load planner do it over ACARS? By the time they'd get around to looking it over, we're already gone.
I just remember it being a little cumbersome to use a laptop. We type the bags, passengers, and runway into an ACARS system and it just uploads the V-Speeds and Weights into the FMS. (we have to hit a confirm button for the V-Speeds). I admit that it used to take forever when we had load planners.