Most clients on a service take about the same effort, so a budget starts as one figure on the service: so many hours a month for bookkeeping, so many a year for the accounts. Every client on the service is measured against it straight away, scaled to how often they are billed. With fee budgets on, the fee each job's time should fit within starts at each client's own price, so there is nothing more to set.
Then deal with the exceptions. The client whose records always arrive in a carrier bag takes the service's budget plus 30%. The one who agreed a lower fee on fewer hours gets their own figures. Change the service's budget later and everyone following it follows, while the figures you agreed stay agreed.
The hours can also follow the step estimates already in your workflows, so the budget and the plan never drift apart.




