Even after reaching Tier Four, Yang Chan's Ox Demon's Mighty Fist could still be upgraded; it hadn't reached its limit. However, it consumed a lot of Potential Points, so he stopped after reaching five percent progress.
Further upgrades would only temper his skin, flesh, and fascia, offering little improvement to his overall power. Although it would make his foundation more solid, Yang Chan was more interested in advancing his Martial Arts Cultivation; that was the key.
Once his Cultivation was high enough, it wouldn't be too late to go back and deepen his foundation.
Besides, cultivators typically stopped focusing on the Ox Demon's Mighty Fist after reaching External Refining of Tendons and Bones Perfection.
A Tier Four Ox Demon's Mighty Fist was already enough for Yang Chan to use the Ox Demon Martial Seal. Once his Ox Demon Martial Seal reached Tier Three Mastery, he would be able to unleash the Nine Oxen's Strength.
