If the plug is further in the chamber it gets more cool fuel and air blowing across it when the intake valve drops off the seat.
They can also make the porcelain contact more of the shell to dump more heat to keep the heat range the same.
On my big power stuff I always made more power with short tipped plugs and more timing. When I go to the dyno I’m hopefully May or June I’m going to bring at least a half dozen different plugs and heat ranges to test.
Unless the piece of crap unloads it’s guts on the dyno, then it will be one or two hero pulls and a clean up.