Workload affects the amount of O2 metabolised and the amount of CO2 produced as a result. If workload is sufficiently high, it also affects the rate at which blood flows.
The rate at which N2 is absorbed by tissues is driven by the pressure gradient between inspired ppN2 and tissue tension of N2. The greater the depth, the greater the pressure, the greater the inspired ppN2. Nitrox reduces the inspired ppN2 by decreasing the fraction of N2 in the breathing gas. The total amount of N2 absorbed is determined by pressure and time.
The volume of gas consumed (ie the breathing rate) has absolutely no effect on the rate at which gas is dissolved into blood and thence tissue. The rate at which the blood is moving MIGHT very slightly affect the rate at which N2 is carried to tissues, but the speed with which N2 is getting into the blood in the lungs is still going to be by far the most important factor and that is entirely independent of how fast a diver is breathing or their heart is pumping. The amount of CO2 produced might have a very slight effect on efficiency of inert gas elimination and breathing efficiency in general. Unless you're Dave Shaw diving a CCR that wasn't designed for it to a depth of 270m, of course, at which point it becomes extremely meaningful, although completely irrelevant to the discussion at hand.
The actual volume of free inert gas involved in a bend is miniscule. Orders of magnitude smaller than the volumes passing through a diver's lungs with every breath. Breathing rate has absolutely nothing to do with DCS. Pressure changes have to do with DCS. A properly planned and conducted ascent will, most of the time, be sufficient to prevent DCS. The rest of the time, well, that's just sheer bad luck and a consequence of the fact that very little is understood about the mechanisms behind the problem - certainly not enough to formulate computer models that will make you safer by voodooing NDLs according to how fast you breathe.
Buy all the computers you like, but you'd be as well off choosing one that changes NDL according to phases of the moon or alignments of the stars. And claiming that it was a computer, rather than switching to air profiles on 32% (and almost certainly more conservative air profiles, at that) that prevented someone from further DCS events? Let's face it, it's a bit of a stretch.
Oh My!
