[Negotiation] What would you do if a supplier offered savings in one area but wanted weaker terms in another?

I would treat that as a trade, not a win, and make the trade explicit. Savings can be real, but if they come with weaker lead-time commitments, looser service levels, or riskier terms, then I want to understand what the business is really buying and what it is giving up.

That is why I do not like celebrating a concession too early. In procurement, value can move around...