The reason the sleeves pull even with the same length is because with a Jantzen shirt, the cuffs are made to fit you properly, i.e. snugly, so the sleeve does not swallow your hand. You need to get your sleeves about 1" longer. You are probably buying your sleeves too short in RTW in order to compensate for the absurdly huge cuff (often 9" or more) normally found on RTW shirts. With a too-large cuff, when you bend your arm the cuff slides up your forearm. A properly fitted shirt will not do this, but you need to have the sleeve long enough.