I have a question

Questions of Mahlo OCF

1. what is the difference of $\psi(M^{M^M})$and $\psi(\chi(M^{M^M}))$?
2. Is $\psi(I(1,0,0...,0))=\psi(M^{M^\omega})$? or $\psi_{\chi(M^\omega)}(0)$?
3. $\psi(M^M+\chi(M^M+\cdots\chi(M^M)\cdots)))=\psi(M^M+M)$?