In the Sequence

Heads Pair Off,
 Central Load The Boat (209,650),
 Partner Trade,
 Center Part Of Load The Boat (1748,650)

Central Load The Boat uses Handles 209 and 650 and evaluates to 
C3B Center Part Of Load The Boat uses Handles 1748 and 650 and 
evaluates to PLUS in the Snapshot Database is no snapshot with 
the handles 1748 and 650. Csds uses the C3B version 209 and 650 instead. 
How does csds do that?

I would like to have the same behaviour with "those diagonally facing Pass Thru) 
and "Jay Walk". the first expression should be evaluated to a lower level 
because I see it as a directional call and not as a C1-call.