If I understand correctly she needs to cancel her extension of stay. If she leaves the country without the cancellation she will be technically on overstay and will need to pay a hefty overstay fee next time she applies for a Non-B visa.
I think anyone can get 7 days extension however after these 7 days you will have to leave. You cannot extend any further or change to another type of extension.
I am in the same situation. When I recently went to file my 90 days report I was told that it wasn't necessary. The immigration didn't accept my report. They didn't provide any evidence that I tried to file it either so it is a bit worrying in case if another inspector would say next time that it was necessary to file and try to fine me. I left a bit confused.