Bruce,
I'd question the validity of Spectrometric Oil Analysis in this case, since the affected areas we are talking about on the engines aren't part of the wet system. Also Borescopes are not the be all and end all.. far from it. Yes you can check parts of the combustion chamber, and you can also check the first few compressor stages and one maybe two stages of the turbine if you are lucky, but the checks are a long way from being comprehensive.
FT