I agree. All actions in SLT are for this.Less to do with "thinking"- more to with layer by layer skill development. When the slt biu is well learned and done- it makes way for the other biu motions later on.
The Jum Sau action teaches us to punch whilst using the inside of the elbow to displace an obstruction (should it be there) when we attack. So Jum Sau is a punch action. Its not a block in my system!!Chum kiu has several possible meanings- a key meaning is "sinking". in the slt jam sao one can learn how to sink the elbow properly- of course there are other motions to teach the sinking.
The idea of Chum Kiu being a form that teaches you how to sink arm bridges or drop elbows is nonsense but I guess you have to meet the right people in order to offer a better way of thinking.
Chum Kiu teaches one to fight in the most simple, efficient and direct way.
No arm on arm BS!!!
GH