-allowable stress flag in material input-

In input windows you set material for pipe.

you have 2 connected pipes:
node 10-20: material A106 pipe (caesar material n.106)
node 20-30: material A312 304L (caesar material n.154)

question1:
the flag "allowable stress" is needed in both nodes 10 and 20?

question2:
if i put the flag only in node 10, the second pipe stress allowables will be those of A106 also if material is different?

question3:
is there a way to force caesaqr to automatically set the flag at every material change?