成唯識論述記 8.96

8.96

述曰：雖餘四因中，亦有因緣，而四因全，五因少分，是方便攝，如上增上多故，偏說非能生因，實理亦是，文不盡理。

The Commentary states: Although within the remaining four causes there are also cause-conditions, nevertheless, all four causes and minor parts of five causes are subsumed under auxiliary means. As stated above, because the dominant [aspect] is predominant, they are specifically spoken of as not being productive causes. In actual principle this is also a case where the text does not fully express the underlying principle.