It seems that the Dek- Block consistently is shown about a foot inside the edge of the floor. I will be building a building on the flooring, and most of the weight of the building will be obviously wherever I place the walls. I was planning to place the wall of the building on the outside edge, but I think the walls should be under a support. I was not planning on building a larger floor than building. Again, my question is specifically, can the Dek-Block be place along the edge of the flooring, instead of under it. I don't care about the looks of that, more concerned about function and sturdiness.

You can place the Dek-block closer to the edge of the support board if you like. The plans are all designed properly for their recommended uses as shown and sometimes the placement of the block one foot in from the end of the support board can save you from having to purchase an extra row of blocks. If you decide to build the floor the size of your shed that will be fine, and if you do alter the plans in any way remember to keep everything spaced properly. There should never be more than 5' between blocks.