Diluted or Undiluted Insulin

I was wondering how many of you might be using diluted Humalog. Since my son was diagnosed, just before turning 1 year old, the Dr.s have been having us dilute his insulin. I mix a new vial each month, 3cc of diluent and 1cc of Humalog, 1/4 strength, and then we just use that vial to draw up his insulin. So when we draw up 1 unit he is really getting .25 units of actual insulin. I think at first when we first started and his doses were so small, it was easier to draw up in the syringe. He is now 2 and using a pump, but they still have me filling it with the diluted Humalog. His carb ratio right now is 1/9, which at first seems like a lot but he would really be 1/36 if it was full strength and I know most kids get more than that for their carbs on full strength. I have been trying to monitor his BG 3 hour post meal and he definitely seems to need more carb coverage. I need to do his meal delays also to get his basals figured out. We just made the switch to the pump last month and then he was sick and vomiting over the Christmas vacation, so we didn’t get off to a very good start. He daily average total insulin, with the pump, is 18-20 units diluted insulin, which would be 4.5-5 units actual insulin. I know everyone is different but I was just wondering how many use diluted Humalog and on average how much insulin per day?