Agreed that depending on the work, bidding by job instead of hour can definitely be a viable way to go (although, admittedly as someone with little experience, it seems like the longer the job gets, the less viable this is? I pitch art commissions by job rather than hour, for example, but that's also because one drawing doesn't take more than a couple of hours. idk how long editing takes on average tho lol).
Although one thing OP might want to be careful about is:
Generally speaking if you're willing to be flexible with pricing, you want to start high and haggle down. I'm not sure if tipping is a common practice in the editorial line of work, but generally speaking most folks won't be willing to pay higher than the baseline if they don't have to.
"Why should I spend $40 on a service being charged $20 if I could instead get a 2nd round of work at $20 or spend the money on any number of other things?"
Marketing services is hard, but a necessary evil I do think that if you start with a high price and no one's biting that lowering the prices little by little until you start finding work is viable if you really need said work. But starting too low is risky and losing out on potential profits.