Dr. sent me home with formula at 9 mo

kezias

We went for our 9 month appt today and got sent home with formula.  LO is 17lb 12 oz.  I was told he was in the 7th percentile, he had previously been in the 15th.  When I asked him if the chart was for all babies or just breastfed babies, he said it was all babies.  LO is healthy, meeting all milestones, doesn't have fat rolls but still has chubby thighs and cheeks.  

I went back to work at 3 weeks (self employed) and still have a good freezer stash and was planning on breastfeeding until 1 year.  LO has not been to quick to start solids, actually, he hardly eats them at our house, but eats good at daycare.  

The Doctor wants me to add formula to the pumped breast milk to get extra calories.  If it were just me and LO at the appointment I would have left the formula in the office, but DH was along.  I am actually thinking about taking it back.  So I come to the almighty bump breastfeeding board for advice.  

Should I need to add formula to pumped breast milk?