803.12 Mandatories
A
"(2) If no line is marked, the mandatory
line is defined as a straight line through
the mandatory, perpendicular to the line
from the tee to the mandatory."

If there are two mandatories in a long fairway, should I regard previous mando as tee for the latter mando?

(Would be logical, compared to "
D. When marking the lie, if the line of
play does not pass the correct side of
the mandatory, then the mandatory
itself shall be considered the hole for the
application of all rules regarding stance,
markers, obstacles, and relief.")

Not unless the TD says so before the round. Maybe this is something the rules committee could discuss changing. Until then, the tee is the tee.

Perhaps I am wrong but this is how would interpret these situations.

If the fairway is a straight line, but the mando's restrict (hyzer/anhyzer routes that significantly reduce the difficulty of the hole) then I would use the Tee box as the perpendicular line reference. However if the fairway is a winding zigzag through woods, etc. I would use the "cut out" fairway as the reference for the perpendicular line.

803.12 Mandatories
A
"(2) If no line is marked, the mandatory
line is defined as a straight line through
the mandatory, perpendicular to the line
from the tee to the mandatory."

If there are two mandatories in a long fairway, should I regard previous mando as tee for the latter mando? <font color="blue"> That would be my ruling as the TD. The TD would be the one who would have to provide such detail in the first place. Still, this seems like a good question to send to the PDGA Rules Committee via the contact link. Please do so. </font>

(Would be logical, compared to "
D. When marking the lie, if the line of
play does not pass the correct side of
the mandatory, then the mandatory
itself shall be considered the hole for the
application of all rules regarding stance,
markers, obstacles, and relief.")