Stop...before we start spinning...What that person was talking about was an "RA commission". Only about 10% of ROTC commissionees get a commission designated RA. The rest get what is called a USAR commission. This has nothing to do with whether you get active duty or reserves. It will have very little impact on your career or future prospects. You'll still be a second lieutenant in the Army no matter what flavor of commission you get.
I would also say that whether you get active or reserves in 4+ years has very little to do with what Battalion you are in (unless you are at an SMC)...it has a lot more to do with how well you do academically, how fit you are, how well you take standardized tests, and how active you are in the ROTC program.
I would recommend you put very little weight into the 10% statement.