In 9 years of DVC ownership, ME has never ever taken less than 45 minutes or more than 1 hour and 15 minutes. And that includes trips to all the DVC resorts except the Poly, and at all different times of year (altho almost always it's a late morning or early afternoon flight arrival time). Order of drop-off at the resorts varies (guess it depends on how many people are going to each resort...ME must use some kind of computer program to figure that out ... it's never the same)...
Our most frequent travel involves a flight that lands right around noon and we're pretty much always at whatever resort we're staying at by 1...that's 9 years, and maybe 30 trips? Give or take...
So, we plan on an hour, but still wouldn't book ADRs for any earlier than 3 hours after we arrive--actually, we seldom set up an ADR at all for arrival day...check-in can take some time, and I usually want to unpack/wind down and then just head to wherever our mood takes us...don't want to "have to" be anywhere immediately after arrival...