Seems fairly straightforward to be honest.
When the season passes went on sale there was, and still is, a variable number of meetings in the season dependent on progress in knockout competitions and whether or not they reach the play-offs.
Alternatives: not to have season passes or to specify that they are valid for the number of league fixtures (28) known in November/December last year.
Standard in just about every other sport I can think of.
Commits the club to providing you with 28 fixtures. It seems equally obvious that as the Ipswich match was a failed fixture it doesn't count towards the 28 but the restaging will. Season pass holders certainly win in this situation but then again if they miss a couple of fixtures for whatever reason they don't get any money back from what they paid for their season pass.