I guess I will resurrect this thread as I have done a couple others tonight since this is the first I have had time to read a lot of these forums since before Ike.
As both an adjuster and a contractor, for years I estimated roofs with a single entry for tear off, and a single entry for installation that included felt, material, labor, metal, etc. My roofing sub still prices his labor this way, but at times I have had to itemize only because contractors using Xactimate started this process a few years ago and I had to figure out why my cost per sq. was coming out different. In some cases their estimate was being padded. And I must add that I have never seen a tear off where the felt and edging could be retained, nor have I ever heard of an adjuster writing an estimate and excluding these items until I read some comments here about it. I can't figure out how it could be done having re-roofed many houses as part of a renovation job.
Since I switched from EZ-Bid in 2008 to Powerclaim, I have have found that most of the contractors roofing prices came fairly close to the single line Powerclaim estimate. However, the Craftsman data base used by Powerclaim (and I believe also Integraclaim) can vary by zip code when at times it should not. I found for instance, that in some major cities, such as Springfield MO, that using a zip code for a rural area outside of Springfield could result in a substantially lower estimate for a roof than using the Springfield zip code, whereas the actual cost was higher due to distance to the job and distance to haul and dump the tear off. When this happens, I use the zip code that results in the correct estimate.
I have always gotten roofing bids or at least cost per sq. quotes from roofers in each area I have adjusted regardless of what software I was using to ensure that I was quoting the correct price. Rarely have I had to submit a supplement. No pricing data base can be 100% accurate, especially when market factors affect the cost after a major hail storm or tornado outbreak. As a result, most of the time I use single line entry for the cost to install then have add'l line items for steep slope and 2 story. Sometimes, however, to make it work right, or to validate a contractors detail estimate, I do break it down by individual component. Since I have not seen any of the data on the claim that is subject to this thread, I can't comment other than to say that I am certain that it is not a software problem, instead is a difference in the way the two estimates were entered, as others have also opined.
I am now having to learn Xactimate for a couple of companies I am going to be adjusting for and will do it however it works in X.