It should put the onus on the person opting to use a part not explicitly defined as "stock" on the car in question.

The "equivalent part rule" handles "equivalent parts" - if the engine mount in question is "the same" as what was delivered on the car when new, no change to the rules is required to cover that eventuality. If the part is DIFFERENT, then someone might try to rationalize it based on the "supersede" rule - as distinct from the "equivalent part" rule. THAT is when it should reasonably have been necessary for someone to get the clarity that results from a line-item allowance.

NOW, the minimum conditions necessary for the ITAC to approve such a line item variance are not entirely clear. I would think that it would be necessary to demonstrate that the stock/original part is truly NLA from any source, including through "equivalent part" aftermarket. But that's a lot of supposition on my part.

K