Here's a dispensation...What dispensation do you suppose Paul is talking about???
Eph 1:10 That in the dispensation of the fullness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:
And here's another dispensation...Any ideas on that???
Eph 3:2 If ye have heard of the dispensation of the grace of God which is given me to you-ward:
Dispensation of the grace of God...What's that??? Could it be that James and Ephesians are in different dispensations???
Col 1:25 Whereof I am made a minister, according to the dispensation of God which is given to me for you, to fulfill the word of God;
The Apostle to the Gentiles was pretty big on dispensational truth...Why wouldn't you be???
The Greek word oikonomia, which the KJV translates as "dispensation" can mean several things, but generally it means an ordering of things and specifically a task of ordering things assigned to someone.
Thus in the examples from 1Cor9, Eph3 and Col, Paul is discussing a "dispensation" or task given to him personally - i.e. God has tasked him with spreading the Gospel.
The example from Eph1 describes God's ordering of the world.
In none of these examples is it even suggested that God has created two or seven or any number of separate orderings of the world ("dispensations") to different ethnic peoples.