Multi data sets rely typically on the fact that there are X copies of the complete data set, each located in a unique location, but with the exact same data names and structures. Like deciding to drive a car down Highyway 1 or a parallel highway called Highway 1. Once on the highway, the car functions exactly the same. The 2 highways are parallel and never meet. Once on one of them you are committed to staying on that road.
Since forms are instatiated only once, it is like only having one highway. Therefore in the Init we have to build a new highway as we go by manually creating the grid. Yuck,