I cannot comment on some technical details here (this is a list for users, after all), but I can say that this add-on has potential and can see some improvements.
One feedback item is command conflict. Currently NVDA+Shift+R is assigned to recognize the currently focused file, which conflicts with row header assignment command in Excel. There are other suggestions (such as using script decorator and using controlTypes.* directly instead of going through api.controlTypes route), but I think resolving command conflicts would make the add-on more useful.
Keep up the good work (as always, an offer to post this on NVDA add-ons list and get some technical feedback is available).