You don't get BAS as part of your paycheck while in OCS. During your time there you are technically enlisted so your BAS money goes directly to wherever it goes to pay for your meals. You might see random amounts of money on your LES for BAH (like the $11.31, $8.70, and $5.51 I got... very random) but I have no idea how they figure that out or why you even get that. Once you are commissioned you will start getting BAS.