Need help identifying the name of a phenomenon (lower price, high volume, increase in total expense)

Currently working on a cost transformation project, and I've been trying to think of this word/phenomenon that I heard a while back.

Basically, in a situation where a commodity goes through a new procurement process that gives a 5% price discount, the buyer ends up buying more of it so the total expenses actually go up because despite the win in pricing, the increased utilization actually hurts the bottom line.

If anyone knows the term or phenomenon that describes this, please help! I'm sure it's something simple, but I just can't get it out of my head.