yeah the shallower the groove the more cable pull. in effect the circumfrence and hence cable pulled is more with a shallower groove.

The other thing to check is the correct actuation of the quadrant..... hence why normal to replace the pawl anyway. is it actuating correctly and self adjusting as it should????

If all is well, then there must be slack in the cable still that needs taking up. Mine was a bodge of a sierra pedal on puma pedal box so the original builder used a spacer.

Yours shouldnt be a bodge but id check if anything is damaged on pedal, clutch lever arm etc.

You could use a spacer to take out the slack but technically its a bodge!