Bose aftermarket spare parts

If you have bose headphones eventually you'll find yourself needing a new set of ear cups and the inside covers / liners.

I recently bought a set and things have improved since I bought sets for my QC-2's years ago, the ear cups actually fit now (required some surgery on the last set), however things still aren't perfect as all of the ones I've seen on eBay (and the like) for my QC35ii have flat inside liners, not curved like the genuine ones (as seen with my manky ones here) that I've removed:

and here

It results in the inside not being covered as it was before:

and so this area is likely going to suffer a little from my ear tips touching that (as you can see the marks on the top photograph if you look carefully) as it was previously covered and now isn't.

Ultimately I think this will reduce the life of my product, so I'll weigh my options, but as they're already nearly 3 years old I'm not sure they'll get the same usage (or if I can apply something else myself).

Just a FYI