I recently attended a black tie event wearing an SWK Thrifty kilt, a "converted waiter's jacket" and accessories from SWK. The whole outfit cost me less than $300.00 to put together.

If it is formal wear you should feel regal and dressed to impress.
I did. And based on the number of compliments I got, others were impressed, as well.

If you are using a waiters jacket or even a converted waiters jacket aren't you just posing in a costume?
No.

Do you really fit in if you are in a waiters tux or are you just wearing a costume to pretend to fit in?
Depends on what you mean by "fit in". That evening, my outfit was as dressy and impressive as any of the other tuxes. More so, since I received numerous compliments on my outfit, something that wasn't happening to the guys in tuxes. On the other hand, if you're hanging around with the sort of person who wouldn't be caught dead in a Chevy Suburban, even though their Cadillac Escalade is just a Suburban with a different trim package, it might make a difference.

I work hard to wear my kilts so that they aren't costumes and in my mind a sportkilt or my PV USA kilt won't cut it for dress occasions because it isn't a tank.
99.9% of the people you meet won't know the difference between a USA kilt and a tank, just like 99.9% of the people won't know the difference between your off the rack tux from Sears, and a hand-sewn suit from Oscar de la Renta. Of those who do know the difference, I'd bet most of them wouldn't care. Those that know the difference and care, are probably people I wouldn't want to associate with, anyway.