[anthony-wohali]

Why not ????

There are millions of inspections done with paint & coating on the surface – only in very special cases coatings are removed. Coating removals could harm structures more than acceptable if the structure shows by NDT to be o.k. (especially in Aerospace).
Environental degraded, aged, dirty and flaking coatings should be removed sa they don’t do the job, than first remove it and afterwards inspect it.
If your inspection procedure, you have written turns out to be critical dealing with the coating, improve it! Usually that is possible by changing freqency signal shape, filter or other instrument settings, tuning / changing the transducer or the delayline, introducing a further inspection step. Use modelling e.g.by CIVA.