Subscription usage-charge Billing apply price according to external attribute

Hello,

We are using usage charge pricing on a Subscription Product.

we have a monthly billing where we update the usage qty via API as it is calculated from an external system.

We have a need to price each month according to a side logic, meaning that the price will be determined each month by a side calculation according to the qty and additional attributes.

Is there a way to determine the specific billing line price each month? What I saw is that there is an option in Pricing for a rate pricing which takes into account the qty and prices according to the qty range. for us the logic is more complicated and we need t pass the billing line price each month together with the usage qty. Or another option would be to create a Pricing matrix that will know to look on another attribute on the billing line and price according to it (and not the qty range).