I think this reinforces that speed of boarding isn't the most important priority to Delta (which I assume isn't be a surprise to them)...this may not slow down boarding but probably doesn't speed it up.

There does sound like one conflict between the article and the chart...the article sounds like Diamonds are only boarding with Delta one (if available) if they are riding there, the chart seems to suggest Diamonds will board with Delta One regardless...I assume the chart is correct (or maybe I am just misinterpreting)