Here my sequence in CSDS:
Heads Star Thru, Double Pass Thru, Peel Off, Touch 1/4, Stretch Counter Rotate, Cross Roll To A Wave, Split Counter Rotate, Stretch Split Counter Rotate, Linear Cycle, Al (ends at home)
The same sequence in SD has to be:
HEADS star thru double pass thru peel off touch 1/4 STRETCH split counter rotate cross roll to a wave split counter rotate STRETCH hinge linear cycle left allemande (at home)
i.e. CSDS: stretch counter rotate equals SD: stretch split counter rotate
and CSDS: stretch split counter rotate equals SD/CSDS: stretch hinge
I wonder which sequence is correct and why?
Stretch requires a 4 (or fewer)-dancer call. The call is done on each side, and the resulting centers (preferably exactly half of the dancers on each side) cross the center line dividing the two sets of dancers, to end on the far side.
From a 2x4, CSDS regards Split Counter Rotate as an 8-dancer call. SD probably regards Split Counter Rotate as a 4-dancer call.
To do a Split Counter Rotate, CSDS applies the 'Split' concept to the overall formation, then each of the two groups does a Counter Rotate with respect to the center of their 'Split' formation.
Hence, for Stretch Split Counter, CSDS behaves as follows: Stretch means do it on each side, so CSDS chops the 2x4 into two parts. Then each part does a Split Counter Rotate, which, from a Mini-Wave Box, would be done on each side (the Split concepts chops the Mini-Wave Box into two Mini-Waves, each of which does a Split Counter Rotate 1/4 - an Arm Turn 1/4).
Similarly, you should call Stretch Circulate instead of Stretch Split Circulate; and Stretch Turn the Key instead of Stretch Split Turn The Key.
In my opinion, SD is wrong with it's implementation of Stretch Split Counter Rotate. The correct call is Stretch Counter Rotate.