Why HOs hate contractors

Over the weekend, my neighbor comes by. She knows I am a commercial GC, and was confused and looking for help. She needed a new roof on her house. House is about 14 years old. As a total WAG, there's about 40 square. 6/12 pitch. Multiple hips. Like most HO's, she got multiple prices. All the houses in our subdivision are around the same age, size, etc. What she was confused about is she could not get two roofers to give her the same story. I think she had 15 prices, ranging from about $11,000 to over $30,000. Most of the roofers were using the same shingle from the same supplier. Some said the existing roof had to be torn off; some said it didn't. Some said she has to have protection board over the old roof; others said a protection membrane. Payment terms were also all over the place, anywher from 10% to 50% down. Two guys wanted her to pay the shingle supplier direct. When she asked about lien waivers, two told her after she made final payment, she could get one. (NOTE -- in Florida, the supplier has lien rights, even if the HO pays the contractor. Note on building permit says to make sure the suppliers are paid before you pay your contractor). Similar issues with warranties. Two people offered a Labor and Material warranty from the shingle manufacturer. (yes, there's an added cost, but I told her it was worth it). From a sales standpoint, one guy apparently told her they looked at her house on Google Earth, so that was all they needed. She said this guy seemed to have the best proposal, but was in a hurry to get to the next house and didn't want to spend any time answering questions. I don't believe she was actually looking for a cheap price -- she was doing what I think she should be -- trying to compare apples to apples. The more questions she asked, the more confused she got. The only real help I ended up giving her was the name of a roofer I had some trust in. I said from a GC standpoint, we go thru this with just about evey trade!