I have heard that too, on the grounds that Lo all but refuses a bottle. I have heard it lots, but am rather dubious? I was told also that I could miss out day feeds altogether, rather than give formula, and just give am/pm feeds.
HC - does your lo eat food yet? If so, you could try diguising the milk? I have done this with our LO. whatever I cook, I add 1-2oz of formula (could use BM) and if its too runny thicken it with babyrice. Also give her lots and lots of yoghurt/dairy type puddings, bits of cheese. I also found she likes thick shakes, because she sees us drinking it. Milk, fruit, yoghurt, whizzed, pretend its a drink, she loves it (we use the frozen summer fruits/banana).
DD is using a beaker, and has very recently just started to drink it herself, not much but some, I use the tommee tippee ones (the same that KZ's Lo fell asleep on in photo!). Unlike yours, she does BF, but I am trying to wean her off due to going back to work.
I don't know how much LO weighs. I have given up putting the pressure on myself/DD to gain more than she is going to. She is fine, has chubby legs, fit, active, eats well, poos and wees fine. At 8mth check she was 14lb 11oz. I was upset as I wanted her to be 15lb!