Can PowerCard macros change sheet variable values or linked bars?

If I have a power that costs a resource to use, is it possible to have it affect a sheet variable that tracks that resource or reduce/increase the linked bar of the token that represents/tracks that resource? For instance, using a power costs 1 Willpower. Can I write in the macro to decrement the current value of Willpower variable by 1 or reduce the linked bar that represents Willpower? Thanks

To write any values to sheets, your either need a Pro subscription for API use, or you need to be in a game created by a Pro subscriber with API scripts installed. Plus/Free can only read values from sheets.

We are in a Pro version of the game. So how would I do that?

The ChatSetAttr API script for character sheets, and TokenMod for token changes. Both are available in the one-click install library - the GM of the game is the only one who can do this part.