Sometimes...it depends on conditions
K.O. is live bacteria that needs a good supply of oxygen from an external source (vent line) to function aerobically. The active ingredient in Odorlos is nitrates, which encourages an aerobic condition in the tank by promoting oxygen release from organic matter (in a holding tank that means the waste itself).
Because K.O. is a bio-active (live bacteria) product, it's "self renewing"...the li'l buggers don't wear out, they multiply...so you shouldn't have to add between pumpouts. Odorlos, otoh, does exhaust itself, requiring a new dose at least every 5 days or even more often in especially hot weather.
So while I especially like K.O. because I developed it...it was the very first bio-active tank product, I'm a realist...not all tanks get enough oxygen from the vent to let it work. So when I don't think it can, I go with Odorlos.
K.O. and Odorlos are the ONLY products I like, btw...they're both 100% enviro-friendly and where one can't work the other usually can.