Quietness doesn't work that way. If your resonator still is packed full of fibreglass and has strategically placed perforated holes, then it'll be quieter compared to 2 poorly designed ones (I'm not saying yours is, just saying in general).If I want more silence, but cannot use two midbox, how about using just one midbox but bigger? Will it be better or the same?
Then your muffler also has to be packed with fiberglass for reduced noise levels. I remember back when I still had my Wira SE stock muffler, originally it was quiet. But over the years it got louder until the extent it was unbearbly loud. When I inspected the exhaust I was expecting to see a hole or 2 but nope. Instead when I knocked the muffler it was as hollow as an empty milo tin. It was pretty obvious! Compared to knocking on a new muffler, it was "thud" vs "konggg"