Subract from a bank of hours function

I have several clients that pre-purchase a bank of hours from me for my consulting time. Is there a way to setup a way that I can set a number of hours to a client and then Toogl subtracts from that instead of simply counting up.
Just a little feature that would save me one or two steps when working with these types of clients.

No one ever helped me on this but I might have found a way around it using the time estimate function but it’s behind a paywall and buried pretty deep.

Switched to Clockify and it was a free feature that was easy to setup to do what I was looking for…