Perhaps there should be two methods?

As a simple blogger/content creator, I want to advertise a piece of content I created that is about a current affair.
I only want that post to run for the voting period. So percentage would definitely be more appropriate because typically the content would be irrelevant after that time.

But lets say I'm a big podcaster such as Joe Rogan with a lot of "evergreen" content. Stuff that always stays relevant. I would want to advertise that stuff all the time to get people to come to my site and see the ads from other sponsors and all the other stupid stuff podcasters do now a days.

Which leads into the next problem.

They are posts on a blockchain. Meaning they are permanent. Yet they can only receive rewards for a short period?
If we want people to take Web3 seriously there has to be a way for people to continue getting rewarded for "evergreen content". Content that will always remain relevant and hold value. If the content still holds a value to someone that is willing to pay for it then it should still be rewarded. IMO that is the number two problem that no one ever talks about.

Personally, I absolutely despise advertising in general. But I do see a need for it for individuals to get their products (content) out there. If ads are done respectfully, tasteful and relevant to what is on the page then I am fine with that.
But I dont like having an irrelevant ad for an irrelevant product shoved in my face when I'm trying to consume content.