How to apply tier based discount based on cumulative usage quantity

Summary:

Hello, Team.
We price subscriptions based on meter readings.

The client requires a discount based on a defined usage quantity, i.e. 0 for the first 100 usage quantities. However, the first 100 usages can occur within the first month or in subsequent months.

We set up the tiered adjustments and established the minimum and maximum volumes. However, the method applies graded discounts to each billing amount without adding usage quantities from the previous bill lines.

Please see the accompanying screenshot, which shows that the amount is zero for all bill lines. However, we anticipate that the amount will be populated for the third bill line (for 30 quantities).