Recoating AP lenses

I just saw something indicated that a lens on an AP 180 f/9 had been recoated recently (~2 years ago) by AP.

I has no idea that this services was available! What are the reasons for recoating a lens on an AP refractor? Damage to coating, upgrading light throughput, something else? Would the lens have to be polished out and refigured to remove the old coating?

I posted here because I think that this issue is of general interest to AP refractor owners.

Hi Phillip
Damage severe enough to cause decrease in the quality of the image,not just cosmetic.Coatings must be polished off and then reapplied. This in itself changes the lens configuration.Its not something you would do on a whim.
Mark