Push Evolution - Ambiguous Wording

[Adam Ormond]

Quote:

An eidolon gains the ability to push creatures away with a successful attack. Select one type of natural attack. Whenever the eidolon makes a successful attack of the selected type, it can attempt a free combat maneuver check. If successful, the target of the attack is pushed 5 feet directly away from the eidolon. This ability only works on creatures of a size equal to or smaller than the eidolon. Creatures pushed in this way do not provoke attacks of opportunity. This evolution can be selected more than once. Its effects do not stack. Each time an eidolon selects this evolution, it applies to a different natural attack. Source: Advanced Player's Guide

So which is it? Does this apply to a Type of attack (e.g. all Bites, Slams, Claws, etc), or to a single natural attack?

Other evolutions (e.g. Reach) are much more explicit, and clearly apply to just a single natural attack, but this one contains language for both type and individual attack.

[GM Jeff]

Select a type of natural attack, say claws.

Whenever you hit with a claw attack, you get a push attempt.

When you gain enough levels to choose another evolution, you can select this one again and choose a different natural attack, say slam.

Now, whenever you hit with a claw attack or a slam attack, you get a push attempt.