No, he'll never have the same exotic weapon two weeks in a row, it's exactly the reasoning you gave is why Bungie has set it to primary, special and then heavy. If they didn't, there could actually be a possibility of Xur having Mida Multi Tool three weeks in a row. If that happened, may god help us.
English
-
Dude did you not buy the last word and then the following week the mida multitool? There is no order its a myth.
-
Next week will be a heavy, friend. Unless an update is released, then it may go back to primary.
-
The update reset the rotation. They had to have this rotation of primary, special and then heavy in place or else Xur would have the possibility of selling the same weapons consecutively. There is no way in hell they want Mida Multi Tool being sold 6 weeks in a row, people would go bat shit crazy.