Yes, that's how it controls the fuel curve. No need to go through the ECU, as it's a piggy-back device. If it's only a K&N air filter and airbox mod, you can get away more easily without accounting for those changes, although it's still ideal to do so. The tuner also has other advantages, one being that it cures throttle snatch. Although, depending on what year the bike was produced, you may not have that problem. You might notice that without the tuner, the bike isn't as smooth and feels less powerful.I will contact Dale. Only mods that i know of is K and N air filter and he took out a restrictive baffle inside the air box and O2 sensor is eliminated. Completely stock exhaust. This tuner runs to each injector and then ground. Nothing to the ECU!
As for the oxygen sensor being eliminated, the bike should also have an O2 bypass installed. This keeps it from throwing a code without the sensor in place.
I'd be interested in hearing what Dale has to say about this.