It's only been recently that anyone has been concerned about those small variances in a baby's head. All of my brothers had flat sides to their heads at one time or another depending on how they were sleeping. The are senior citizens now and again have very little hair and their heads are an appropriate shape.
Sometimes a child has a medical condition that does require treatment so that their head has enough room for the brain or the head isn't growing properly but the average baby's head is perfect just as it is. There is no such thing as a perfectly round head.
If the doctor isn't concerned, relax and stop micro managing your daughter's head. It's shape will change thru out her baby and toddler time until the bones fuse. The skull has those separations to allow for change.
I know, we want to do the best for our babies. Sometimes the best is to relax and not worry about minor things.