My 17 yr old son has decided he might be asthmatic so took himself along to the docs and now has to do the usual one month diagnostic peak flows. He has been given a vitalograph meter. I have tried looking up on the internet to find average normal recordings but can't find specific vitalograph ones. Does this meter give similar reading to the normal EU peak fllow meter or lower? I tried doing it this morning and got 50 less than my pf 3hrs ago on my EU meter.