I too have been getting estimates, for my house..
EVERYONE in SC puts down a "grid".. & the price from "the top installer" was almost 9k.!!! {small house}
I got 2 more & they were 7200. & 7500..
I ran into a couple of fellas from W Virginia that were doing some metal repair work on the building at work..{SC}
& I asked THEM about my house..
They freaked out about the "other" estimates..
THEY SAID.. they don't use a grid & put down an insulation foam pad.. directly to the existing shingles.. he showed it to me.. nice..
He said that, once you walk on a grid, the screws pull on the metal panels & u get a leak..
THATS THE WAY we do it in WV.. but I'll do it ANY WAY YOU WANT..
Price will be 5k.. NO MORE THAN 5500.00 just because we'll have to get a hotel..
Then I was "thinkin'".. just how many times do you actually get up there & walk on the grid.???
I asked him, are you REALLY WILLING to drive to SC from WV for this little bit of money??
He said, THATS what we do.. We spend 10 months outta the year in this van.. chasin a dollar..
BTW> they did some REALLY NICE work on the building at work..