It's not just the geographical region that affects the moisture content. The wood in Florida is probably stored in an indoor warehouse, and in shipping it's stored inside a truck. And besides that, the difference between Florida and the Mid-Atlantic can still be enough to cause issues if you don't account for it.

In short, if the seller tells you to acclimate for at least a week, acclimate for at least a week. A few extra days is nothing compared to the time it would take to fix the problems that can arise from inadequate acclimation.

As for the acclimation process itself, make sure you store the decking outside near where it will be installed, and allow for plenty of air flow. Keep it elevated off the ground, and use scrap wood to create gaps between the boards. Do not cover it with a tarp; if you're worried about rain, you can put a piece of plywood over top.