He was awed by Roger and upped his game traveling with him, as was specifically said that his strength grew dramatically.
That said Oda only confirmed both used CoC, not that Oden's was advanced.
THEY'RE NOT TOUCHING was specifically used as a sign post by both Oden, seeing Roger/WB's adv CoC clash and Law for Luffy/Kaido's adv CoC clash, he was awed at the outlandish effectand power of adv CoC, you are jumping throuhg multiple hoops, which you don't even need to to claim Oden's final attack was adv CoC, when you make the ridiculous claim that the attack he used against the boar had it, just to excuse Zoro for not having the same physical cues as the confirmed users of adv CoC (i.e. the yonkos and Roger).