For example the CPI for the last 4 years has been about 10% in total, whereas the past 4 years has seen just 4% in wage rise - so those that have left and rejoined have seen a proportion of their take home grow by 6% over those in the Regulars
Interesting point and one with history. In fairness the numbers are pretty marginal these days and more of academic interest than anything else I would imagine.
However, I saw presentation on the identical situation in seventies, when inflation was running as much as 20%
and yearly military payrises were not a given. Some dude from PMC contrasted a Wg Cdr who left in the early seventies at an option point, with one who stayed in full term. As I recall the one who left earlier ended up on a considerably higher pension even though he served several years less. (PS to avoid confusion, the presentation was about this seventies situation - I saw it in the nineties, I'm old but I'm not that old!)