I'm afraid I do not understand.

If L7=L1-L2, and at limit D2=0 and T2 is installation temperature, mean that we should always do the following:

L1=W+P1+D1+T1 (OPE)
L2=W+P1 (SUS)
L3=WNC (SUS)
L4=L1-L3 (EXP) =[(W-WNC)+P1]+D1+T1

which we don't.

Or do I miss something?

Best regards,