Different markup on different customers

How would you handle different markup % on different customer without having a second screen open to check cost and selling price of inventory the whole time? Example Customer A buys a lot of inventory each month and markup is 15% on him, other customers that buys now and then or very little have 25% markup.

Currently this feature is not available, however there has been mentions of having pricing levels in the future but there has been no implementation timetable.

At this moment we markup at max and apply discount for Customer A. I was hoping someone had a better way for this scenario. It would be nice to apply this feature in the customer tab when created.