The add-on is in a silo that prevents being triggered by a script or formula. Google sees it as a security feature.
It's not exactly what you want but the add-on has a scheduling feature. I haven't been a fan of Google's scheduling features on the whole (not very reliable or timely), but this one for the add-on seems to be pretty reliable these days.
Also, I was able to train a high-level manager to run the add-on when he wanted reports. A button would be better but a little bit of patience works too.