Raw arm strength is many times reflected by in line carry. Throws that lack in line carry look like there is less arm strength than there really is. Balls that sink or tail, especially on longer throws, lose velocity because distance magnifies poor rotation. That's why it is imperative to be able to throw with 6-12 rotation.To ensure this the ball must be released directly above your fingers.This is usually controlled by your trunk angle at release.( Straight up or slightly tilted to your glove side)
Throwing with a stripped ball gives you immediate feed back. You can also warm up down the foul line & focus on the ball staying on line without deviating left or right(It's usually right)