My DD1 slept through the first time at 12 weeks on the EASY routine, (with dreamfeed at 11pm) and DD2 slept through the first time at 9 weeks using the same feeding routine. I do think there must be some logic that if babies have all their daily calories in the day, and are kept up during the day, with frequent (but short E.G 1 1/2 hours) naps then the night waking should be less.
With both of mine when I knew they were taking enough food in the day and doing the short naps thing then I used suger water for a few nights (warmed up, and with a bottle of milk on standby) to see how that worked. And for me it did!
But, I cannot clain that both DDs slept through EVERY night from 12 and 9 weeks. But, DD1 slept through every night from 4 months (I went back to work at 5 months and night waking was already a distant memory) and DD2 who is 13 weeks does occasionally wake about 3am, I pop the dummy in, and that is that til about 0630-0700.
With both of mine being under 2, I just don't think I could cope at all if I was still feeding in the night - shattered as it is!!