Shaun P - I am very interested to see how others respond to your comment, "It would be interesting to see if endo's find the relevant dosage level for an individual child of say 17mg/m2 and stay on that dosage level instead of waiting for kids to fall out of a range and then increasing it." 

That is the way I thought it should work. I was very concerned because my 3 year old has been on anywhere from 21 mg/m2/day (while on the liquid) to as low as 3.9mg/m2/day. I talked to his endo and ped. and asked if we shouldn't be able to find a dose (mg/m2) that worked for him and stay with it. Both said it doesn't work that way but I never did really get an explanation as to why.

Great posts on this topic! (Carol, as usual you amaze me with your knowledge)