Well if you look at the bells and roof its virtually identical but i think hashis version had to have been stronger or kishi was trolling i mean ps sword plus a full bijuu dama and it doesnt incinerate on impact..? And oros version did even though it was against 4 tailed naruto. Maybe hashi had a stronger summon, you know like how gamakichi and gamabunta are both toads but bunta is stronger/bigger. If you want to know my theory a part of it is:
oro found hashiramas scroll of jutsus, the one he carried with him on his back. Amongst other things, on it was the contract for summoning the rashommons, which oro signed his name on. When he fought naruto, at the chakra level he was at, he was only able to summon a lesser tier version of the rashommon defence. This also ties in with oros jutsu obssesion imo.
Its a lot more but thats one part of it(the theory).