A map doesn't "kick in", it's a preset tune that adjusts the fuel so your bike doesn't run lean (or rich). That's why there are so many maps, because there are so many different combinations of pipes/airboxes. Use a Vic map with a Vic intake, S&S map with a S&S intake. Not all maps are perfect for all combinations so some folks go with a fuel controller.
But don't over-complicate it - there are thousands of posts on maps/combinations. You were right, both dealers were correct, just two different schools of thought. Now you have to decide how you want the bike set up.
The Vic Shop, Inc