This is the Thread where this issue came up recently. Don't know why I couldn't search it up in RV.net. Used gOOgle and here it is. She did what I remember, dug the sealant away from the screws, installed the brackets, then applied new sealant.
I agree this mounting approach is disappointing. Disturbing a sealed roof is worrisome. I can picture, though, were starting out with the mounting right flat with the flange could result in the cover being closer to the roof surface. Was just up there today, and brackets mounted over sealant look pretty cockeyed.
