Does Mills have an arm problem or a calculation problem?

I was watching the summary of this week's game and I noticed what I've been seeing in Mills is overall pretty consistent- his decision making is largely fine but sometimes the throw itself is what causes the problem. I found that to be the case with both of his interceptions this week. You can see where he's trying to go with the ball and the decision is fine, even if not the best, but the throw is bad. I've been seeing this over all of his games that he'll have a throw where the ball placement is poor. This was something he struggled with at times in college too. However, I'm not sure it's necessarily his arm power, maybe with so little experience and starts, he hasn't yet figured out ball placement consistently. It's like he underestimates where he needs to put the ball or can't calculate how much of a spin he needs to put on the ball. What do you guys think? I really hope he figures it out.