It is so hard to compare the amounts of meds taken by our children. Even if two babies who weigh the same and are the same height may take different amounts of meds. Those with CAH still produce some cortisone and the amounts vary greatly, it just isn't enough for healthy hormone levels. What's important is his blood draw levels. If they are okay and he's growing normal and eating and sleeping okay then I would try not to worry. When my daughter was 3 months old (she is small!) she was on .1mg of florinef and 6mg cortef perday. This was of the cortef suspension, orange stuff. The suspension by Upjohn was taken off the market because it didn't work. So when she switched to the pill version her dosage lowered to 5mg per day which she is still on at 16 pounds. You say 1.5ml so I am assuming thathe is on a suspension made by the pharmacist that you must get each week? If this is true make sure you shake it well to resuspend the medicine. I recommend getting the pill. It's much easier. We drop the amount of pill in the oral syringe and suck up water. Wait to dissolve and give. Repeat to get all the meds. This way is VERY accurate. She was on liquid sodium but we could never get it to stay down. We started just giving her salt on our finger a few time a day and it was much easier. Of course we discussed it with her endo. Now that she's eating table food we just salt her food a little especially on hot days. Blessings!