Anmarie,
it sounds as though you are bringing up several different issues.
WRT the medication - who is prescribing it? The boys' pediatrician based on the counselor's recommendation? A pyschiatrist? The dosage you describe is a starting dosage. My son takes the same medication - the starting point is 10mg and then usually it is increased up to a certain point depending on several factors - age, weight, effectiveness. My difficult child could take up to 40mg but the rebound and sleeplessness went through the roof between 30-40mg. My difficult child's psychiatrist had me up the medication dosage ever 3-5 days and I was given a response/report form that I copied and filled out every day to help determine whether or not the medication was effective. It may appear that the prescribing physician is treating the boys like the same, but the medication and dosage you describe is a common first trial for most kids with AD/HD these days. Metadate CD is basically Ritalin (the brand name for methylphenadate <sp?>
it is packed to be time released to last longer than the traditional 3.5-4 hours that Ritalin works. Ritalin has been the first drug of choice for AD/HD for the past 30+ years, due to the fact your oldest boy doesn't have a diagnosis of Bipolar, it may be the drug trial is to rule out AD/HD.
It sounds as though you need to get into see the prescribing physician asap to discuss the side effects. Make sure to write down your observations daily and if able to give times. This is important information for the prescribing physician to be able to make decisions to change medications.
WRT the IEP discontinued due to low IQ... Did you son qualify for Sped Ed services on his last evaluation due to specific learning disabilities (SLD)or a health impairment? In order to continue to receive specially designed instruction (SDI) under the SLD category there needs to be a statistically significant difference between a student's IQ score and performance on standardized educational testing. E.G. a student with an IQ of 115 (on the high side) in the 4th grade who tests out on a educational assessment as performing at the 2nd grade level would qualify as SLD. If your son's IQ was say in the 25th% and he's performing school work at the 25th% he wouldn't qualify under that category. Did you have a medical diagnosis for your son when they discontinued the IEP? If not, they may not have been able to qualify him in a category. If his diagnosis is new then I would certainly approach the school with the new diagnosis and request a evaluation for Special Education services again.