The formula checks specifically say that one coupon per formula is allowed, and you can't double (or triple+) more, but I've heard of some stores allowing it on the same transaction.
If you have coupons that are going to run out, I'd just buy however many containers of formula in relation to the amount of coupons that you have. Either way, you're going to need the formula. You can always try to see if your local store will allow you to double up.
Our local toysrus is pretty lenient. You can always do one transaction per container of formula, if they give you a hard time. You will use the formula anyway.
Re: ? Formula checks
The formula checks specifically say that one coupon per formula is allowed, and you can't double (or triple+) more, but I've heard of some stores allowing it on the same transaction.
If you have coupons that are going to run out, I'd just buy however many containers of formula in relation to the amount of coupons that you have. Either way, you're going to need the formula. You can always try to see if your local store will allow you to double up.