Originally Posted by hwichlaz:
Former LC here, and that is NOT true unless it's outdated milk from the freezer. If she is feeding at the breast and pumping, the most recently pumped milk will reflect the child's changing needs. The child needs roughly 1 ounce per hour over a 24 hour period. The fat nutrient levels in the milk change over time based on the child's needs. This is why milk that's been in the freezer for months should only be as back up...and supplies should be rotated regularly. Most kids get much more milk from the breast than they do from a bottle so don't freak out if the child is with you 10 hours but doesn't drink 10 ounces of milk. 
I was thinking that she is sending in frozen back up milk and not freshly pumped milk from the previous day so you are correct.