I would have to respectfully disagree with the above. You cannot stop in any cities you desire as long as they are within the MPM. Certain (most) cities are not allowed because they are not part of a published route. I experienced this problem first-hand.

There appear to be two general rules that must be met when booking stopovers:

1) Total trip must be within MPM limit (or +5% or whatever. Delta does not seem to be overly anal about this).

2) Stopovers cannot occur in most cities. Can definitely occur in cities that are part of published fare between origin and destination. May be possible in other cities but depends on what agent says.

Here is a simple example: You can't go NYC - Moscow - Athens on SkyTeam with a stopover in Moscow, at least not on one single award booking. This is because Moscow is not a valid stopover between NYC and Athens as it is not part of a published fare. I guess a rebellious ticketing agent might allow it, but it should not be expected. Let's also assume for the sake of the example that this trip is within MPM limits.

The reason the Scandinavian flight you mention was allowed was because AMS is a legal stopover between NYC and some Scandinavian city. The MPM issue is quirky and can be circumvented because other published fares have a greater miles traveled. You can always find an alternative, and if you prove it to Delta, they increase the allowable MPM. But the stopover you chose (AMS), was still inherently a legal SkyTeam stopover for this flight. You would not be able to connect through Rome for example, even if you were hypothetically within the MPM.