Scope
How do I set a plan price with a fixed price for a specific range of units and then by unit price?
Solution
Let's take an example that if the units are between 1-10, you want to charge the customer $50, and for each extra unit (after 10) you want to charge $15/unit.
1) So for this, a “flat fee” plan for the first 10 users with a fixed price of $50 can be created.
2) Then, you can create an “addon” of “per unit”-based pricing, and define a $15 price per unit.
So in addition to that plan, the customer can add the addon and choose the number of units, and the customer will be charged accordingly.