His usual cultivation speed is one transformation every 6 to 8 years, thanks to the upgrade of the Mountain Foundation divine ability to level 5.
So he should have spent at least 8 years advancing to the fourth transformation because there is a bottleneck between the third transformation and the fourth transformation.
In fact, he expected to spend more than 8 years overcoming the bottleneck because of the lack of mana in Aries and the severe lack of time to focus on cultivation. If there was anything that would shorten his cultivation speed, he expected it to be gained from the resources in Aries, not through fighting.
But now that he has been enlightened, he expects his future cultivation speed to pick up and even become able to match Thor's. He expects that he will be able to cheat just like Thor.
