Ok, many thanks, I think I am getting it. Why in his explanation he puts D1 in the OPE case
"CASE 1 (OPE) W+D1+T1+P1"
??
This D1 should be a consequence, an effect not an imposition. I mean that from the OPE case you get D1 and you apply it to the OCC case L3.
I think this formally uncorrect but it doesn't make any difference from a results standpoint.
Did I say right things or i am still missing something?