One note: the CC company will correct your (my) math, adjusting the total as necessary. Example: a base bill of $98 and a tip of $15 will be charged $113 even if the diner writes in $110 as the total.

IMHO its best to take this directly to the CC company. They are in the best position to see a pattern of fraud by the restaurant. A perfunctory apology and a correction really doesn't do it for me. - and no, I'm not angling for a free meal 'next time'.