So this is a new feature in the Sale Order Module in Sage 100 ERP v2014. I attended a great session at Sage Summit that Shelley Arnold and Gina Thompson did and explained the details. The idea is now we can do Item pricing by total quantity.
Motivated customers can buy goods and services with flexible pricing. Beat the competition with the ability to establish pricing by total quantity, by item category and for the totals purchased by product line. Encourage large purchases across multiple produce lines, or by combining specific items, colors, or sizes.
This can be setup in Sales Order Options bottom left side of the screen. You can see a detailed description in the blog I wrote for ERPVAR.com.