Is there something about the slam rules I'm missing?

[Refplace]

I made some martial styles with a few custom techniques for animals in my Animal Combat article.
But that kind of attack can be handled multiple ways. I dont really consider it a slam so much as the poster above suggested a Move and Attack.
Other factors. The prey is likely running away, reducing damage from velocity rather than increasing it if both ran at each other.
The animal can also use up velocity/momentum by leaping and then falling instead of a full speed direct impact.
I should have added such a note to that article!
Here is a sample technique from that article, it has a few new techniques plus a style for various types of tactics. Ambush Predators; Rushing or Stalking Predators; Pack Predators; and Prey Animals for example.
Deadly Pounce

Average

Defaults: Brawling, Jumping, or Wrestling.
Prerequisites: Brawling, Jumping, and Wrestling and
requires four legs; can’t exceed prerequisite skill+2.

This is an All-Out Attack (Double) that combines a Pounce
(p. B372) followed by a grapple attempt. It allows up to a half
move forward with an extra yard of reach and +4 to hit for a
slam, followed by a bite to grapple. Roll DX, Acrobatics, or
Jumping to stay on your feet afterward.