Alternative Fee Arrangements used by law firms could be adopted for this. The following are most commonly employed.
1. Fixed Fee
2. Capped Fee
3. Volume Discount
4. Early Payment Discount
5. Fixed Rate
6. Blended Rate
7. Retainer
The idea is you have a lawyer draft a complex agreement with multiple fee arrangements, most involving some math. And provide an invoice with pre-agreed work descriptions. Lawyers use UTBMS. You should be able to come up with something that you and your client agree. This makes your invoice look more "professional" and easy for the accounting departments of your clients.
The idea is you have a lawyer draft a complex agreement with multiple fee arrangements, most involving some math. And provide an invoice with pre-agreed work descriptions. Lawyers use UTBMS. You should be able to come up with something that you and your client agree. This makes your invoice look more "professional" and easy for the accounting departments of your clients.