Q: Why is Sku Grid removing my items from eBay's volume pricing?
A: Sku Grid is not modifying volume pricing or removing. Volume pricing is a "promotion" on eBay. If you revise your listing price at all, eBay removes items from "promotions". Sku Grid does an initial repricing on your items after you add them to the grid, so unless you created an override formula to produce the same listing price that you have at that time, then your price has likely changed and eBay removed the item from volume pricing.