Working capital and inventory are always very challenging points to negotiate and there is no fixed template for this discussion. I would recommend speaking to industry professionals to get better idea on how to value the inventory

First address if Price (P) includes inventory (X) or is it P +X? Is P+X a significant increase? Does P+X make it 5x multiple or 7x multiple? Other issues are: How is X counted, costed and reported? Is it perpetual? How frequently does the seller take write-off? Is X high b/c seller bought for supply chain issue? Or X has a spike for another reason? If X is really high, then, get into operations i.e. seller's habit of buying everything, lack of ERP systems, etc. and if you can improve. You may find that the profit is bogus (A) or the opposite (B) depending on accounting. If A, run. If B, then convert that to your advantage. Once you get your arms around P+X, then there are many ways to mitigate the risk of stale, slow, obsolete. I have sold many businesses with such challenges. Happy to walk you through.