As far as back-to-back sancs can get back to back payments if their order is established that way.
The issue he may be talking about is described by me in Github
Sanctuaries still occasionally receive back-to-back rewards. The last one I saw was 44966 and 44967 which were both received by MN BMzQQ29EcQyNanxpi1afjLYaxwx5exsfQJ.
This skews the expected rate of return for Sanctuaries as the back-to-back rewards are sporadic and unpredictable. But this goes against the Economics page which states "38.5% is given to the longest waiting Sanctuary".