What SHOULD have happened, was Zetsu should have showed up right before Madara got sealed in the Sand Tomb, Madara should have got his eye back inside the tomb, and THEN he should have used a giant Almight Push to blast apart the tomb and knock back the Tailed Beasts.
THAT series of events would have made sense.
That's what I attributed it to. That Madara's Push is better because Madara is much stronger than Pain(which, I don't have a problem with in general, the idea that a more powerful person uses a technique that someone else used that doesn't follow the exact same rules it did before, because different characters have different limitations).
My other explanation was that it was just animated really poorly.