I thought if you exchange the A 2836 (ICHS) for the ETA 2893 you get CHS. But then the arrangement is the same in both movements.
I never thought about it. I heard 2893 is the better movement, more reliable and with CHS, jumping hour hands true gmt. Im not sure if thats true.
Also i heard people wish they still use the 2893 in the gmt watch since it's an amazing movement, but factory have stop using it in their rep.