Please see #1: “…As lōbha, dōsa, mōha are removed gradually, the wisdom (pannā) gained in that process automatically reduces alōbha, adōsa, amōha as needed. An Arahant has removed all six; alōbha, adōsa, amōha must be cultivated all the way up to the Arahant stage.”
It is strange that the good cetasika shall be reduced and cultivated up to the Arahant stage. Especially amoha is needed to gain panna. Why should amoha be removed?