Grit Spending and Signature Deed

[Meudian]

So I was talking with my GM recently andwe might be running into a problem that might end up breaking the character. So I have a gunslinger (pistolero) that is fast approaching level 12 and getting a Signature Deed which will end up being Up Close and Deadly. Now my character has 7 grit and I can burn 4 to add 3d6 to all four attacks. Now the issue comes up as when I make Up Close and Deadly my Signature Deed I can do and extra 3d6 per attack so long as I have 1 grit point. So my character will be doing 4 attacks for 1d8+10 +1d6(fire) +3d6(Up Close & Deadly). And then at level 15 Up Close & Deadly goes to 4d6. No I looked in Ultimate Combat and I haven't found anything limiting grit spending per round, or how many times you can use deeds in a round. But does anyone think this might be getting slightly broken?

[Pinky's Brain]

Instead of +3d6 per attack a fighter archer will have +3 damage from weapon training and greater bracers of archery, a significantly better attack bonus and an extra attack from manyshot.

Meh.

[Petty Alchemy]

How the blazes do you have 7 grit? Did you take 16 wis and Extra Grit twice?

Anyway yeah, that's the point of signature deed. If you're scared of doing damage, you can take Twin Shot Knockdown as your sig, and prone two enemies per round (with rapidshot).