In Section V and Section VI of the CRS Commentary the following must be noted:
Section V. C. Entity Accounts with respect to which reporting is required. With respect to Preexisting Entity Accounts described in paragraph B, only accounts that are held by one or more Entities that are Reportable Persons, or by Passive NFEs with one or more Controlling Persons who are Reportable Persons, shall be treated as Reportable Accounts.
As you aware under CRS an Entity Account may become reportable twice. That is based on the residency of the entity itself (for which the CRS standard considered a Trust to be an Entity) or where the Entity is also a Passive NFE, then the look through provisions applies and if the controlling persons are reportable persons then the account become reportable again based on the Controlling persons. Section VI. A. 2. has a similar provision and a similar requirement.
Looking at the Implementation handbook, the conclusions there are the same. The Implementation handbook gives an example on page 121, paragraph 283, which speaks to a Trust that is also a Passive NFE. In that case because the Trust is also a Passive NFE then the look through approach has to be applied. It then goes on to identify who can be identified as Controlling persons of a Trust [who is a Passive NFE]. If however, the Trust is not a Passive NFE, there is nowhere in the Implementation handbook that suggests that the look through approach has to be applied simply because the account holder is a Trust.