I'm a little confused. If I understood the article correctly the argument is that the rate of expansion isn't increasing but staying constant while the rate time passes is slowing.
Given that the rate of expansion is a measure of distance over time wouldn't the net effect be identical?
I guess the argument is that dark energy is in fact a manifestation of the physical rules of our universe, but in the end doesn't that violate the laws of energy conservation? Effectively if we observe acceleration of distant parts of the galaxy due to present time traveling slower relative to historic, where does the energy that causes the acceleration come from?
This is reminiscent of Feynman's explanation about magnetism [1] in that it leads back to the original question.