Once in ketosis, the only hunger you feel is psychological. My LLC used to say that being in ketosis was like being pregnant - 'you either are or you aren't, dear, there's no 'a bit''
Al I know is that CD recommend you don't doublepack as people who are sensitive to cards may be kicked out by having all their pack carbs in a short space of time but occasionally I have had to have all three packs in the space of an hour and I have not felt hungry as a result.
I don't know why people would try pushing themselves, but I do know when I was on route to management it was interesting seeing how quickly I could get back to ketosis after I came out - the less glycogen you make with the carbs you intake the quicker you're back in - which means people who eat a small carby meal may come out of ketosis, but be back in 12 hours later as one small meal does not make enough glycogen to kick you out of ketosis for three days.
I'd recommend not mucking about with it as once you go back to square one, you have huge problems differentiating between real and psychological tricksy hunger.