The extra half inch was a snap decision to put the PSR7 stack into the DL7. The PSR7 G2 stack was developed in the PSR7 and dropped ear noise like 4DB to like 136DB on a 16" .308 gas gun, improved tone, and dropped FRP while reducing muzzle flash. I don't really know much about how it performs because we made that decision without testing the can in the middle of a very busy manufacturing year. We had at that point put a PSR7 stack with one extra baffle into 3 cans - the KAC compatible cans, and all had performed well, indicating the stack is pretty versatile inside the boundaries of .308 applications. The KAC compatible cans were a little different in that they have pretty short length in front of the muzzle of the attached firearms and no muzzle brakes so those applications weren't "ideal applications" for better performance.
We had not really been completely satisfied by the DL7, because we don't really like cans that teter on the edge of being loud. A lot of loud cans exist and are popular in the industry- like the Dead Air Sandman S, or many of the B&T cans. However we kind of think loud cans are shitty. And the DL7 was already more quiet than those, but we just thought it warranted an extra baffle, and at that point the number of baffles could allow the PSR7 G2 stack to fit, and we went that route because it was working well in the 4 applications we had used it in.
We made several decisions like that this year, and some of those we had prototyped and tested previously and some not- like the GP5 and 7 became tubeless cans with Explorr stacks and caps- the 7 with one extra baffle. The DL5 is getting a baffle system designed for demonstration to the USMC that we put 4 months of R&D into is an example on the other side of the envelope. Some of the cans that didn't have the most improved flash reduction caps are getting them. I would be surprised if in every case we made a decision to change the systems, they didn't perform better than previously.