RTE117

I've searched forever now, even on the web, and asked people and no one has a concrete answer so I figured to ask here. The BTM's in the 6BTM ignition and the actual BTM unit itself work by a vaccum line connected to the manifold. When it senses boost it pulls the timing accordingly, per every lbs of boost it pulls X amount of timing. Does this work for nitrous injection as well? How does it read the amount of nitrous? Or does it just read it as 1 psi? I'm not sure since nitrous is injected as such a high pressure. Thanks