That's right, the author states: "Each scenario represents an event in Underearth's 'history'. Each is a tactical situation which is completely different from any other scenario."
Then follows two pages of notes which introduce and discuss strategies for each scenario in further detail.
The article ends by noting that other scenarios were developed and play-tested but dropped from the final release (such as a multi-player assault on a strong, prepared Dwarf defense).
Unfortunately no additional scenarios are included but a table of stats for about 10 new unit counters are given (covering companies of elves and various monster types).
Did the article happen to list a point cost for the new units?