[bermanoid]

I agree with all of this, but I'd warn that unless you really know what you're doing and what can go wrong, jumping from weekly billing to project billing can be super dangerous and you're taking on a lot of risk. Most people aren't great at locking in scope for projects, let alone estimating the work it will take once the scope is locked; once you agree to per-project billing, you've committed and are on the hook for errors on both fronts.