Roofing needs replaced does this quote sound right?

we got an estimate for dimensional roofing by a local contractor referred to us by a real estate agent.friend of our.The insurance allowed for replacement of the roof and gutters on both the home and small exterior out building minus1000 deductible.We were quite pleased with the check amt however he came and quoted us almost all the check amt for the house only.with the roof and gutters.The gutters have been hanging off and there is some wood damage that would have to be replaced.He says he has to rip off the old roof which is one layer of flat shingles in order for his warranty to be legit.Is he just trying to get more money or is this true.The damage is at the end of the roof where the gutters are.The home was built in 1985.Someone please explain this to me.Thanks in advance