Ritalin LA or Focalin XR? | ADHD Information

has anyone had exprience changing med from Ritalin to Focalin xr? My son is on the 12 hr (2 pills 5mg) and seem to doing niclely, However, my daughter is also on Ritalin la 8hr. and doesn't like to take more after 4pm(even though i think she needs it for homework overload).Is ther less side effects with Focalin. especially with loss of appetite (in Ritalin).  I'm wondering if she will do better with the 12hr or will it affect her since she has been on Ritalin for a year.My son takes the Folcalin xr and hasn't had any problems with eating too little or too much.  We've been on it for about 2 months. 
We've also been able to keep  it to 5 mg with a nutritional diet less sugars etc...

Ritalin LA is supposed to last 8 hours.  Focalin XR is supposed to last 8 hours.  What 12 hour med are you talking about?  Concerta (which is the only stimulant that lasts 10 to 12 hours)?