User blog comment:Boboris02/Ordinal Analysis of Theories/@comment-11227630-20180213093537

TREE(n) exceeds all functions provable recursive in $$\text{ACA}_0+\Pi^1_2\text{ - BI}$$, according to Harvey Friedman. If your value of PTO of $$\text{ACA}_0+\Pi^1_2\text{ - BI}$$ is right, then TREE function is stronger than what we previously thought.