Q, with all due respect to the effort you've put into this bot: If it doesn't do well as premium, it's because it isn't ready to be a premium bot IMO. I can only use it when babysitting, and even then I run into regular problems. I don't post every minor issue, as I've seen you've been bombarded with requests for changes, and working your ass off to get them in. But take my most recent session, for example.
I logged in having completed a task prior to logging out. It tele'd me to Varrock. Went to grab a new task. Got it -- Fire Giants. Tele'd back to Varrock. Then immediately used a glory to Edgeville, never banked or re-upped the inventory, and was about to try to use the Edgeville lever to level 51 wilderness, wearing full gear, before I manually stopped it.
I'll post logs. And again, I have mad respect for the time you've put in, and entirely understand if at this point you chalk it up as time lost and move on. I just wanted to let you know that I can't see myself paying for it, in it's current state, when I don't feel comfortable leaving it running when not present to babysit it. And yet, had it gotten to a point where I could do so, at least for a couple of hours, I'd have attempted 99 slayer on a maxed account, paying the whole way.