This...like Swenson's method and the Kart Easy-Fit system...does provide a repeatable spot for the barrel to return to, but it comes with a built-in problem if the barrel is positioned too far down. Instead of the lugs absorbing the recoil stresses low on the lug, it places them closer to the middle...which results in rapid lug deformation or even cracking or shearing of the lug...depending on how much of the lug is used to handle the load.
The preference is to get the barrel as far into the slide as it will go so as to place those forces in the corner of the lug at the junction of lug and barrel and lug and slide.
There's a side benefit to using all the vertical engagement possible.
Because the barrel tilts up at the rear, the forces are directed on an angle, placing the lug in compression. When a barrel is fitted "down" the way the picture illustrates...most or all of that is lost, and the lug is taking the brunt in a straight line. This condition isn't as critical with lightly-loaded "softball" target ammunition...but it can cause a problem pretty quickly with +P loadings, or even standard hardball.
Pictured below is a barrel that was fired about 200 times with insufficient vertical lug engagement. In this case, only about 50% of the lug's height was in play.
For these reasons, I only use the Kart Easy-Fit system in pistols that will allow good vertical engagement. By the time the barrel is ready to go, nearly all the fitting pads are gone. Those that don't have that get the hard-fit barrels and are fitted "up" by using the oversized lower lug.
