The idea of different 'dispensations' is not limited to dispys.

WCF 7:6 Under the gospel, when Christ the substance was exhibited, the ordinances in which this covenant is dispensed, are the preaching of the Word, and the administration of the sacraments of Baptism and the Lord's Supper; which, though fewer in number, and administered with more simplicity and less outward glory, yet in them it is held forth in more fullness, evidence, and spiritual efficacy, to all nations, both Jews and Gentiles; and is called the New Testament. There are not, therefore, two covenants of grace differing in substance, but one and the same under various dispensations.

The dispensational distinctive, as I understand it, is that there are HUGE discontinuities between the dispensations. Church/Israel for example.

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