What is the big deal? The code allows for 3 reroofing with asphalt roofing.
With the allowable three reroofing and adding the dead load, using the 10
psf dead load limit seems appropriate for the city to go by. We have tables
in the code which we can design by and still not resort to vertical load or
lateral load calcs. Since the code allows this activity, I see no reason to
get excited. Change the code.
RI Ogawa, PE