Is your current agency billing you the exact same amount every month? Are you getting the exact same amount of work each month?
Forget straight retainers, they don’t work. At the end of each month, either the client isn’t getting all that they’ve paid for or the agency is over servicing the client. When the client/agency relationship is unbalanced, it’s destined for failure.
BBPR builds budgets for partners based on the estimated number of hours a project takes to complete and then bills for those hours as they’re accrued on a monthly basis. No more, no less.
When a program is presented to a client, the estimated number of hours (and accompanying hourly rate) for each program component is included. At the end of the month, clients are invoiced only for the time spent on their projects that month. If a project was completed under the estimated amount of time, you save money. If a major news outlet is asking to tour your factory in China and do a multi-page spread… well, that’s a nice budget problem to have.