I don't want to get a brouhaha going, but it doesn't matter whether you do the inside sizing with a expander OR outside sizing with a bushing...as long as the neck wall is uniform the bullet release will be uniform as close as can be expected. You can adjust bullet release in both methods by changing bushings or polishing the button.
I like the outside better as the case is center at the top and bottom of the case at the top of the stroke but the case is left flopping around at the bottom when the expander button is pulled through even if the case is still supported at the neck.
But it really doesn't matter all that much except with the accuracy potential of a benchrest gun and each shooter has their own particular methods. When I was in the sport 40 years ago I used a Wilson seater fitted precisely to the chamber and cases neck turned to the nth degree and most chamber necks were so close NONE of the cases were sized...normal springback of the brass was all that was needed.
I have no idea what benchresters are doing now, but I still build my own rifles, stick to what is readily available, turn the necks on ALL my shooters from 17FB to 510 Makatak(50 cal blownout Rigby case) and manage to keep most well below half inch 3-5 shot groups.
Eveyone has their preferences and enjoy their own level of accuracy...if it works for you, keep doing it...or try something new to see if it works or not...
Luck
