For anyone selling through agencies (ads, media, SaaS resellers, marketplaces): when an agency gets credit or committed funding that's shared across its clients, how do you model it?

We've seen setups where the agency's funding and each client's spend end up as separate, manually linked records, and revenue rollups and remaining-balance tracking break down.

Curious: What CRM are you on (Salesforce, HubSpot, Dynamics, in-house)?

Custom objects, spreadsheets, or a finance system?

What still breaks?