I aim to cum twice in a hour with a recovery break between them. RO doesn't do much for me personally and, call me a selfish bastard, I'm paying so my satisfaction comes above the prossies.
That said, I have been known to go down for 5 - 10 minutes whilst in recovery mode, the 10 minute end of things has usually been when 69ing.
One prossie insisted on RO to get her 'wet enough' which I thought was a sodding cheek. She was up her own arse and I'd stretched to 150 quid an hour for her which made matters worse. I intentionally made a laughably bad attempt at RO - imagine a bulldog furiously licking an ice cream with the associated nasal snorts - she didn't put up with it for too long
As I got ready to leave she commended me on giving the worst oral she'd ever had. In return I commended her on being the worlds most stingy prossie as far as the lube is concerned.