In the early 1990s when
DVC began, Disney World's highest demand seasons were mid-Feb to end of April, summer from mid-June to mid-Aug, Thanksgiving time, and at the very high end, Christmas week and the two Easter weeks. May was more medium to lower demand while all of Fall, other than Christmas and Thanksgiving, had low demand. October at the time was a big nothing with no monthly events, and for rentals from Disney, it was in a low cost season.
Thus, when DVC began, the annual point structures were set up to match the seasonal demand for WDW in general at the time. That structure has remained to this day despite that DVC seasonal demand has become something significantly different from WDW in general demand, and WDW in general demand has itself changed particularly for October and other Fall time.
As a result, April is today part of magic season, except that the two Easter weeks are premier season, and Oct is lower point cost choice season, despite that DVC demand for Oct today makes all of April look like off-season.