The 20 factors on the wholesome side are the removal of the 10 types of miccha ditthi and getting to the 10 factors in the Noble Path: Sammā Ditthi, Sammā Sankappa, Sammā Vācā, Sammā Kammanta, Sammā Ājiva, Sammā Vāyāma, Sammā Sati, Sammā Samādhi, Sammā Ñāna, and Sammā Vimutti.
– Note here that one needs to complete two more factors (Sammā Ñāna, and Sammā Vimutti) beyond the eightfold path factors to become an Arahant.
When one has one or more miccha ditthi, one is on the wrong path. Those are the first 10 factors on the unwholesome side.
When one has many of those miccha ditthi, one will be going down the wrong path, and will end up with unwholesome 10 factors that are opposite of the 10 factors for an Arahant: micchā Ditthi, micchā Sankappa, micchā Vācā, micchā Kammanta, micchā Ājiva, micchā Vāyāma, micchā Sati, micchā Samādhi, micchā Ñāna, and micchā Vimutti.
So, those are 20 factors to the unwholesome side.
Even though those last 10 factors are not explicitly stated in the Maha Cattarisaka sutta, they are implicated there. Those are explicitly stated in several suttas including “Sādhu Sutta (AN 10.134)” and “Micchatta Sutta (an 10.103)“.
I may need to re-write the post on Maha Cattarisaka sutta to make this more clear.