Thanks, the fact that you are offering these changes, tells me that you also feel uncomfortable with this feature of using the 0V rail as the reference input to the error amplifier?
I mean, surely the reference voltage cannot be the negative supply rail voltage itself?....the opamp needs to develop an overdrive so that it can respond to the input signal.....and how can it do this if the inut signal cannot possibly go below the reference voltage?.......i am saying that the input signal (the signal on the inverting input of the opamp) cannot go below the reference input, (which is 0V) and it absolutely needs to be able to do that , in order that it can behave like an opamp should in this case. Well, i know that the input signal "can" go below the 0V reference voltage, but the opamp does not "know" what that voltage is, because going below 0V is going below the opamps 0V rail, and the opamp does not know what voltages are below its 0V supply rail.
Surely you agree, that this is at best "shoddy" workmanship?