Maybe RCI is actually bumping up deposits that turn out to be "peak weeks", whose calendars often aren't established in South Africa when RCI deposits are first made.
If so, that's as it should be. It means the deposit calculator won't ever be very accurate, is all.
Sudwala markets its weeks as either peak, or not - sort of a cross between floating and fixed, where if you own peak you'll always get a SA holiday week, and if you don't, you never will - definitely different from Dikhololo, I formerly owned at both - so maybe Sudwala & other similar SA resort's TPU's won't change much.
OTOH Dikhololo and maybe Louveld Lodge and maybe some others, either assign floating weeks, or are actual fixed weeks regardless of SA peak week schedule - so some will get lucky, and what you deposit might end up being peak.
Just speculatin'.