I'm curious as to how map mileages are listed when there are alternative routes. I just got my new Cyclosource catalog in the mail, and I looked up the "Northern Tier + North Lakes" route. So it tells me that if I buy the complete set, it is 4651 miles. Then each of the 12 maps in the set are listed individually, each with a mileage. If I add up the 12 mileages of the individual maps, I only get 4399 miles, 252 miles short of the set total. Now I know that there are several options on this route (e.g., (1) you can go to Waterton Lakes NP in Canada or go through East Glacier to Cut Bank, (2) you can go through Grand Rapids MN or take the shortcut to Dalbo, (3) you can ferry across Lake Michigan from Ludington MI or go around the north side and cross the Mackinac Strait). I also know that the maps contain roads you won't need if taking the North Lakes alternative (e.g., the last half of North Lakes Section 3 takes you back to the NT in Indiana, which you don't need if you're taking the Lake Erie Connector).
So, to refine my question, what do the mileages shown for map segments or map sets include? Are they a sum of all the roads mapped, including the alternatives? Do they count the shortest alternative? The longest alternative? The "normal" alternative? And how do you come up with 4651 miles for the Northern Tier + North Lakes map set.