How to handle quantity price breaks from a vendor

I'm looking for a strategy to handle quantity price breaks from a vendor.  We do not have the quantity pricing feature turned on but we have one vendor that offers a normal cost for qty 1-9 but additional discounts at qty 10-24 and a deeper discount at qty 25+ but only for some items, it's not universal.  The quantity pricing feature seems to be focused more on the sales side and doesn't seem like the right answer here (and turning on features like that always has myriad downstream consequences). 

I'm leaning toward custom fields on the item records and scripts to get the pricing right on transactions but I'm really hoping there is a better way.  We use the cost estimate feature to track profit per line item so the cost of each item has to be correct on all sales transactions (even quotes) so it will require code for lots of transaction types, not just purchase orders.  I would generate a price list with the various costs for each quantity level external to NetSuite so I could import a complete list with all costs already calculated if that