Power Grappling and 'grappling rolls'

[Icelander]

The Power Grappling Perk on MA p. 51 gives the option of replacing normally DX-based 'grappling rolls' with ST-based rolls. It also allows the replacement of ST rolls with Sumo Wrestling or Wrestling bonuses with ST-based rolls against Judo, Sumo Wrestling or Wrestling.

The second benefit is straight-forward to adjudicate. A ST roll (with a possible +1 or +2) becomes a ST-based skill roll.

But the first one is tricker. What are 'grappling rolls'? Are those any rolls against grappling skills (with the caveat that the perk explicitly does not affect rolls to hit and active defences)? Any rolls you make for 'Actions after a Grapple' in MA?

In particular, are either of the following 'grappling rolls'?

a) Ready an item while grappled.
b) Rolls to inflict damage with Arm Lock or Leg Lock?

I like the Perk, but I feel that it may incorporate too many effects for one trait. For one thing, I dislike how it benefits the cliched weak, but skilled, akidoka just as much, or more, than it benefits more realistic grappling MMA fighters with ST and DX scores closer to each other.

I'm thinking of splitting it up into Power Grappling (allow substitutions of ST-based rolls for DX-based ones) and Cunning Grappler (allow ST-based skill instead of ST rolls). But that's not workable if the benefit under Power Grappling applies too seldom to be any use.