There are no differences, I shot both the long and short version and could never tell any difference. The max loads on that powder are way conservative. When I first started loading H4831, the max load was 66 grains with a 140 grain bullet in a 7 mag. My best load and max load was 68.5 grains with the 140 grain boat tail. If I went to 69 grains, I started having problems.
In my opinion, they lowered the max because of inconsistencies in the powder between batches and are playing it safe.