Looks like 25yd is "select slug" range even for Flite Control loads. That ain't nothin' to bragg about. Vang/back-bored cylinder bore 870's are reputed to give 10in 00buck patterns at 35yd.
It'd depend on the particular shotgun and the backstop for me. One of ours kept half the pellets in the A box at 35 yards. If the bad guy were standing against a wall or good backstop I'd send a round at him and start closing the distance.
And personally I'd just transition to a pistol inside of 40-45 yards rather than a slug changeover.
