There's an easy and simple way to disprove this thread without having to make this go to ten pages. First off, Kishimoto does scaling pretty well in terms of portrayal. In one on one fights, especially for rivals, during clashes, there's always a display of equality. The original Chidori vs Rasengan clash, the Shinsenjuu vs Armoured PS Kurama clash and most recently, the panels showing the Indra's Arrow Bow from the Bijuu PS contrary to Naruto's Ashura's Avatar. Now, PS and Naruto's regular avatar are right around or equal when it comes to durability, correct? When the Indra's Arrow and RS clash happened, both avatars were knocked out of the air but not destroyed. They slowly dissipated until they dissipated on the ground (evident by the size of the fall when they both fell to the ground and the way Kishi drew the impact). So that is concrete proof that they're equal in durability. Just like the equal PS and Kurama Avatar! So I don't get why you think that Ashura's Avatar wouldn't again stalemate the Bijuu PS. It's maniacal to think otherwise.
