According the the new radius selector system the effective radius (r^) = radius inputed (r) - 1. However, the game is detecting entities further than that, but not the old system r^ = r. Instead, the equation seems to be r^ = r - 1 + .46 (+/- .01)
This allows a command block set to detect entities r=1 to still find them. (This should be impossible as it should be acting like the old r=0 detecting entities only on the same block. r = .5)