This is the Kusala Niddesa and only some of the maha kusala citta and the lokuttara kusala citta have the panna-link. The others don’t have it.
“…Tattha katame kusalamūlā? Alobho, adoso, amoho—ime vuccanti “kusalamūlā”. …”
There is the explanation for 4 maha kusala citta in kamavacara.
The first includes all 3 good roots: alobho, adosa, amoho; with amoho as “Tattha katamo amoho? Yā paññā pajānanā … pe … amoho dhammavicayo sammādiṭṭhi— ayaṃ vuccati “amoho”..
The second has only amoho, adoso.
The third has also all 3 good roots with “Tattha katame kusalamūlā? Alobho, adoso, amoho—ime vuccanti “kusalamūlā”
The fourth has only 2 good roots: alobho, adoso.
All 4 are kusala citta even without amoho. In rupavacara and arupavacara kusala citta is also no deeper level of amoho mentioned.
It seems to me that “kusala” here also refers to punna in general.
Bhikku Bodhis Comprehensive Manual of Abhidhamma explains those kamavacara-kusalacittani as:
“These eight types of consciousness are called wholesome (kusala) or meritious (punna) because they inhibit the defilements and produce good results. …”