Tens of thousands of roofs have been measured by this method by adjusters over the years. I was taught this method in property estimating school. I would also guess over 99.5 % of new home builders who order material off the plans also use this method.
This is another old storm story, but true. In 1990 I worked a very large hail storm with thousands of claims. The vendor was recognized as one of the best. When we had our first meeting the company mans speech was along these lines. Thank you for arriving so soon, we feel very fortunate to have this group of hand picked adjusters who we consider the best in regards to knowledge and integrity. Therefore; all we want is a handwritten estimate ,service bill on three part carbon paper. It was a very good storm.
I was in the energy adjusting field for the next four years. In the spring of 1994 I contacted the vendor and was sent out the next day. When I arrived I saw several ole buds from 1990 and after the meeting I ask "What happened" All four gave their version. The condensed version was: these honorable men were so good for the first 5 months of 1991 they did not have to climb roofs to see the damage and could walk around the house and measure the roof and other areas with their trained strides and feet.
Needless to say in 1994 about one of 10 of our files were rechecked and I understand they (carriers) think we should be ruled with iron first today as we are not honorable people as we report to be.
Any one want to hear any more little dirty secrets ?