Most AAS unless oral is an intramuscular injection. Some of the AAS types without going into allot of detail are slow acting and fast acting. Like Test Cypionate is a slow absorbing. takes roughly 6 weeks to build up your test level then the shots are maintenance, it has a half life of 72 hours. so 72 hours after injection your Test levels peak. so allot of guys will inject twice a week. some AAS works much faster and requires injections daily or every other day. So it really doesn't matter which large muscle you use, Butt, calves, biceps, quads, delts. The problem is with the amount of injections and how much of the AAS the muscle can hold. For some people the butt is the least painful, as well can usual hold the largest injections. To answer your question directly, there is no added benefit to injecting different muscles, it all transfers to your bloodstream and your body will metabolites it and use where it is required. the objective of the injection is to raise your blood stream levels for your body to use.
