"**Increases** the weight multiplier by x" I would take as straight addition, with the variable "x" being defined as (power spent + 2).

So if you have 17.5 CP in that ability the weight increase is x6, Pushing costs PR2 and the gravity costs PR3, so the weight multiplier increase is 3+2=5, for a total multiplier of 11.

Or is it supposed to be PR3 + PR2 +2 for an increase of 7?

"'Pushing' increases the Weight Multiplier by x(Power spent +2) for 1 round."

Which method is correct:

Weight Multiplier x8 plus Power Spent +2

or

Weight Multiplier x8 multiplied by Power Spent +2

Say your character's Weight Multiplier is 8.

You spend 2 Power to Push*.

Your Weight Multiplier is now 8 x (2+2) = 32, for one round.

*It could be a different amount, if your character has Willpower C).

"'Pushing' increases the Weight Multiplier by x(Power spent +2) for 1 round."

Which method is correct:

Weight Multiplier x8 plus Power Spent +2

or

Weight Multiplier x8 multiplied by Power Spent +2

Say your character's Weight Multiplier is 8.

You spend 2 Power to Push*.

Your Weight Multiplier is now 8 x (2+2) = 32, for one round.

*It could be a different amount, if your character has Willpower C).

Thanks for the clarification, @jeff

As an aside, it seems like a case could easily be made for putting 5 CPs into Gravity Increase, then placing 20 into Energy for +40 Power. That much extra Power is always good--Rolling With Damage and Saves, Pushing, fueling your other Abilities. Then you can just Push your Gravity Control to make it stronger. With as short as most combats are, this makes more sense than simply putting 20 Points into Gravity Increase. As you pointed out, Willpower C can increase this as well. It's a great tool all-around, so throw that in for more Gravity Pushing shenanigans, on top of its other uses. I feel a build brewing...