Why did the deal size change?

The deal size is automatically determined by the products entered for the lead. When you add or remove products for a lead the deal size is recalculated. You can override the calculated amount after all products are entered.

For example, if the lead is eligible for a discount, you can manually change the total of the deal size to apply the discount. However, the application overrides the deal size total if you add or remove a product from the lead after having manually adjusted the deal size. In this case, you have to reapply the manual change.