You gotta remember that medium and low modes are PWM generated and there's some efficiency loss as a result. IIRC, the lowest mode only has like 50% efficiency or something like that.
It sorta fits. I think it messes with the o-ring and prevents contact at the switch ring unless you add a metal spacer.
More discussion here: https://budgetlightforum.com/t/-/10558?page=1#comment-247502
Check this post: https://budgetlightforum.com/t/-/10558?page=2#comment-270184
Looks like I/O was shipping some of theirs with the Convoy logo already.