How to work with a client outside the exchange?

Question

Freelance

I must say right away that we are talking about hourly payment because everything is clear with a fixed price.
Let's assume a situation that a client was found on the exchange, made an order for him through the exchange, the work is completed, then he immediately or after some time wants something else. Work, let me remind you, hourly. So the question is how to organize this so that everything is transparent from the point of view of the client and the contractor. That is, to have a billing that the client is likely to trust and how to pay for it. Perhaps an analogue of odek or elance with a guaranteed payment, but with a lower percentage.
The goal, of course, is to optimize the costs of paying for the exchange.
I think that formally this does not violate the rules, since the order received through the exchange is executed and paid for through it, and this does not apply to other orders received in private.

Answer 1

Organization through special accounting services of work with timers.
Or, you can agree as a business day. For example, $20-30/hour for an 8 hour workday. Every day progress report.