If you are going to have mufflers, crossovers are a good thing.
It's been a while since I investigated the theory. I recall it was presented in detail along with dyno test results in old Hot Rod magazines. In the 80's, I think. It would probably take quite a while to find the issue, which I probably still have stored away in a box...somewhere.
Here's what I recall from fallible memory.
Each cylinder "thinks" it has two outlets, less backpressure for high RPM. The "scavenge effect" of the opposite cylinder's exhaust velocity helps draw flow from the exhaust port. This results in improved low and midrange torque with the same high range horsepower as you would get from open headers.
The pulse frequency of each outlet doubles and reduces in intensity. This can result is an actual 5 db decrease in audible noise emitted and a "perceived" lower pitch exhaust note. Making it sound much quieter to human ears.
I went through a similar investigation last year with my CX500 that I still don't have finally sorted. It came with a Mac 2 into 1 instead of the stock 2 into 2 with H box crossover. To get good power I had to really keep the RPMS up. With a very sharp, piercing exhaust note drawing pained looks from anyone nearby. It was clear I was going to need earplugs under the helmet for any freeway operation if I wanted to save my remaining hearing response. (A few years of playing in Rock N Roll bands during the seventies.)
I ended up buying a nearly new CX500 stock exhaust system off ebay. What a difference. Throttle twist is now meaningfull without dropping two gears. Without a helmet, wind noise is more obtrusive than exhaust note. And, I can test drive the bike on residential streets without concern for neighbors calling the cops for disturbing the peace.
Just about had the engine and jetting all sorted and reliable until a tear in the in tank filter passed a bunch of rust scale into the freshly rebuilt carbs.
I'm not cleaning them again until I get the replacement tank cleaned and the filter sorted
But, I was given a pretty cherry 85 CB700S Nighthawk. That got inserted ahead of the CX in the repair que. Turn sigs and Riffle fairing repaint and it's done. Then onto tank cleaning...
Anyway, hope this helps.
