French to English Tech/Engineering Automotive / Cars & Trucks spare parts

This is a brochure presenting servicing packages for industrial machinery.

Included in the flat-rate is the replacement of certain components, and in some cases the customer receives a reimbursement or reduction depending on the condition of the "contrepartie".

I assume that in a context of replacements, this "contrepartie" simply refers to one of the parts in this 'swap', i.e. either the used part taken back by the manufacturer or the refurbished part supplied to the customer.

Here are two conditions under the standard replacement option:
"Jusqu’à x% d’économie sur le prix du neuf ... selon composant et modèle machine, et pour une contrepartie restituée en bon état"
"Remboursement rapide des contreparties selon les critères d’acceptation YYY"

Would anyone have a solution that works well in these two cases?

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