Indeed, Smokey, RollsRoyce is VERY specific about these items and it is thus so on the very first RR big fan as well, the RB.211.
When in doubt folks, follow the written procedures, as they have been accessed as the best, by the manufacturer.
Do not substitute...follow the book.
I can recall several occasions with the vibration system on the RB.211, and a few pilots thinking...'oh, we just ignore that, it ain't reliable'....followed by a big BANG, and much consternation.
