Of course, that's the bottom line figure for xG when it comes down to it. I suppose you could also adjust for strength of opposition faced so far but that's a lot more more work so it's near enough.
I only brought that other stuff up because of the specific context of the thread. OP talking about chance conversion rate being low, Greck asking the question as to whether our chances were that great to begin with, presumably to try and tease out whether we were missing big chances or just shooting from bad positions. Chance quality doesn't look too high on that basis.
We could skip both chance conversion rate and xG per shot and go straight to xG per game like you say (or total xG if we're willing to ignore that some teams have played more than others). So we're on 1.37 xG per game on fbref, ranked 9th. Take penalties out of equation and they think we're worth exactly 1 goal a game in open play, ranked 11th. They have us down for 12 goals, must be because one was an OG and they've omitted that from their calculations unless they made an error.
Or if we prefer understat's slightly different xG model, they think we should have scored 10.83 so far, which is ranked 12th and have done quite well to have scored 13.
At Understat as you probably already know we can see who they reckon is doing well or not in terms of tucking away chances. With Rashford and Martial not scoring that often so far this season they don't think it's because they're missing lots of chances, more that they're not having good chances to begin with. They think Martial should be on 1 goal (to the nearest goal) and Rashford's 2 so far is about right.