Huge difference in the way an inline verses a terminal filter works. Sunisshinings filter has a chamber that is filled with air and that overpressure causes an even flow of air out the cylinder of carbon. In addition of being of greater volume and thus handling more airflow at less resistence, it allows air to move through the carbon slowly allowing more odor particles to be captured. It can also be run with a lower CFM fan (I use the same 6" inline).
The big issue is air fissures forming in your filter. Airflow restrictions will cause air to be forced down the path of least resistence, this can lead to odor leaks as only a tiny portion of the carbon in the bag is being used. The commercial style filters are built to utilize more carbon at a lower pressure which will greatly improve odor controll.
