My boy switched from Similac to Nestle NAN HA. The reason why he switched is because he has an allergy to the high lactose content in normal FM which would lead to an allergic rash also known as eczema.
There are many reasons for colic. Sometimes when there's too much gas build up in the tummy, and they can't pass it out, they would keep crying. Usually the breaking down of lactose requires extra work by the body so that might be producing slightly more gas. An allergic reaction would also cause tummy aches which would also lead to a bout of crying.
HA milk is still cow's milk. It's not soy milk and it's not goat's milk.