I'm slightly confused, they've told you to stop giving her as much milk just because she's dropped percentiles slightly? Is she still putting on weight? All the guidelines say that milk should be their main source of food for the first year and solids should only gradually increase. I would say that if she's not losing weight, by all means offer her solids more often but don't try and force the issue, otherwise you run the risk of making food a battleground. And remember that they put on weight much more slowly as they become more active, because they're burning it off - Kaya didn't put any weight on between 6 months and 12 months because she was just so active.
Except once babies start drinking a certain amount of milk they risk becomming extremely overweight as milk is very fatty and full of vitamins. And a baby this young becomming overweight is dangerous and can result in later weight issues in life.
The reason weaning by 6 months is recommended is to help prevent this, as well as to get the baby used to foods. Weaning properly usually results in a good steady weight gain.
2-6 month reccomendation: 23-35oz per 24 hours
6 months when weaning recommendation: 24oz
When weaning is fully establish: 20oz
At 9 months babies have cows milk integrated....
Im not sure where people get the info that milk is supposed to be their main source of food? Once weaning starts it isnt... Milk becomes a source of vitamins.