It could well be normal rotation. I presume that they still do this. During my service we used to rotate on a fairly regular basis with other Regiments, like the 5th skins etc. This allowed us to get to know our opposite numbers in other Regiments which let us have a fairly ease handover. i.e if handing over the troop to the incomers and you were X number of items down, and x number of items ( WOCS not included) they would accept the takeover without any shortage showing. next time you took over from them you would accept their up,s and downs. So you got to know who you were dealing with.
A word is enough for a wise man