Starting Shift Point

So, I understand they make runs on a chassis dyno not in first gear, but if the purpose of adjusting stall is to get the engine into the power band as quickly as possible from low gear. Why? Once you have made the 1-2 shift, the goal of shifting is keeping the engine in the power band? Wouldn’t second gear be a better compromise? Be careful testing stall, it is hard on things.
Get you a copy of the Mopar engine book and read it. Then you'll understand.