I see. I didn't delve deeply enough into this at first to see that they were exclusively talking about 4th down decisions. I thought they were saying that the net total of all decisions by all coaches was an average of 3/4 of a loss per season per coach.
Still though, I think it makes more sense to frame the stat in terms of expected points rather than expected wins/losses. This is one of those rare statistical moments where I think it's inappropriate to consider each event independently of the opposing team. For example I didn't mind McDermott trotting out Bass 6 times against the Jets when we beat them 18-10 but had he done the same against a high powered offense it would have been way too conservative.