The fundamental difference with the SA330 was that there was an abundance of evidence of the deterioration - in fact it was amazing it lasted as long as it did given the amount of metal it was making. The issue was that the Chief Engineer did not know the difference between 7square millimeters, and 7 millimeters squared and was sticking the debris on his graph paper waiting for it to get to 49 square millimeters.........
In fairness (for want of a better term) the AAIB did a poll of the UK CAA surveyors and found about a 50/50 split.