quote; It depends on trap to vent distance and you can't waste stack vent bathroom fixtures.
I don't know what THAT means, but we ALWAYS "stack vent" bathroom fixtures, at least on the upper level. As long as that top 1 1/2" is for a sink and it is within the prescribed limits for a trap you are okay. You probably also only needed a 3" riser, assuming this is not the lower level of a two story building, but if there is a bathroom above it, then everything we said is invalid. I am not sure why the second image since the only difference is that it does not show the septic connection.