so flux staircasing is not an issue - lucky you.
I see what you mean...with this "on/off burst mode method", you could in theory, end up with the burst taking the mag current higher and higher with each burst, though as you know, with the schem provided, the mag current will have discharged well down by the time the next burst starts.
Also , another theoretical problem with this approach, is that the power bursts could show up in the mains supply current, (and if loads of them on the mains, could make the mains very on/off if they all "lined up") however, fortunately, the upstream boost pfc output capacitor bank would supply all the bursts, so its ok.
I bet there are gazillions of offline PSUs out there, providing 50mVpkpk ripple, with a frequency compensated, opto coupled feedback loop, when its just a rough dc bus thats needed, and even +/-5% vout ripple wouldnt matter.....the PSU of the top post makes life so much easier.
The SMPS revolution is coming!