Dear Lisa,
Allergies are a special area, and it can be very difficult to get correct information. It is very stressful for mothers! (I know because I have been there and done that personally, as well as in my experience with mothers I work with.)
At this age your baby still needs 700-800mls of breastmilk per day - which seems to be what your little one is having. Generally babies who take this much milk will grow and thrive. Food is *in addition* to breastmilk. What you are observing is exactly the reason why it is usually not recommended to give solids at this age. Research shows that low cal solids (rice and vegies and the other first foods babies take are usually low in calories) displaces milk from the diet. Generally they need more breastmilk rather than more food. Babies who suffer from allergies often do gain weight more slowly than their counterparts. They use more calories just to keep their bodies intact, their immune system is under constant asault. It's not really possible or helpful to compare what the formula tin says to what your baby needs.
Many mothers find that the key to getting more milk in is trying smaller, more frequent feeds. It is important in situations like this to watch the baby, not the *numbers* - they will grow differently to other babies and their will be multiple factors involved. It is really, really important in these situations that breatmilk feeding is preserved. Breastmilk supports your baby's immune system and reduces inections. Feel free to ask more questions. You are doing a really great job in very difficult circumstances