Hmm to me that does not make any sense. The rear exhaust piping is where the gas velocity is the slowest, especially if coming from a smaller diameter pipe. It essentially would "hit a wall" if you will and come to a halt in terms of velocity. Many tuners actually would make the rear exhaust piping smaller to actually help keep the velocity up from the inherently slower exhaust by the time it reaches there.
Not sure there is any logic in that at all or its way beyond anything I have ever understood about physics and fluid dynamics