I think that it has been stated before, Bell are terrified at the prospect of being liable for ANY defect on the machine down the line. What better way of absolving themselves than by requiring an almost total rebuild. They can then claim that any subsequent fault was not related.
The American legal system SUCKS!! We as aviators have paid and paid and paid...... and in this case, once again there is a huge bill, why, because Bell needs to cover its a**e from a legal point of view!