Sid,

You have my sympathy but without your file you do not have a warranty and
you don't have any idea how many layers of shingles are already on the roof.
I'm afraid that tossing on another layer of shingles may lead to a roof
collapse. You also don't seem to have any plan for addressing the curling,
which may be a symptom of a problem with your roof deck.
Go bug the neighbors to try to find the roof file. Look for your
cancelled check, that will give you the roofer's name. He should be able to
tell you based on the price whether he tore off the old shingles. If you
can't find any records I think you need to do a tear off. That will be a big
job.

Dave M.