User blog comment:Plexioth- xD/Monster Hunter 3 Ultimate/@comment-5043481-20130125161532/@comment-208.125.139.98-20130125182423

Elemental skills: Fire atk up+1 1.1x +2 1.2x

Water atk up +1 1.1x +2 1.2x

Thunder atk up+1 1.1x +2 1.2x

Ice atk up+1 1.1x +2 1.2x

Dragon atk up+1 1.1x +2 1.2x

Elemental atk up 1.1x

EAU and any other element up skill do stack.

The difference between tri and p3rds system is the addition of individual elemental atk skills and the nerf of EAU from 1.2x to 1.1x.

Status skills: Status atk up+1 1.1x +2 1.2x

In p3rd status atk was given a nerf: instead of 10 points to status for 1.2x to 15 points of status for 1.2x

I do not know if this is 100% correct for mh3u but this is the case for p3rd.