1) Set withdraw trigger instead.
Yes, withdraw trigger would be a useful additional feature for affiliates. But billing cycle is important too, because it allows to limit the duration of advertising campaign. Right now each advertiser's payment has duration of 30 days (after the last payment is made, the ads will be shown for 30 days, so advertisers have to pay monthly to continue advertising). I think many advertisers would prefer to pay daily or weekly, or to have an intensive but short advertising campaign for just few days (e. g. in case of some event or promotion).
3) see prior post
I don't have Round Robin algorithm there, but I like your idea. Maybe it could be an option for affiliate (to not show repeating ads).
1QaZxSw2 and Tritonio, thank you for your participation!