The contracts were done years ago, what they now need is Operators to regularly audit that it is 100 achieved, and if something has slipped below spec (and I mean even 0.5% off spec, not wait until blatantly miles off), and whilst off spec need to withhold hefty chunks of payments until sorted.
No company will go to commercial court chasing outstanding payment for a reduction on invoice because they have failed to deliver 100% of their contract. They might moan and threaten legal action, but will reluctantly sort it first, only then will they actually implement legal action.
So Operator need to check things vs any defect sheets, and if that means taking micrometers, cleanliness swabs or whatever to ensure not just 99% of condition then that's what they need to do. If a defect has been 'missed' or under reported then action needs to be taken against failure to report correctly.
No point in having specifications and measurements in a contract if they are not enforced to nth degree at frequent intervals. Got to get out of mindset of doesn't matter, and nearly good enough is ok.