Part 7-3 defines the following presence condition for lnNs (AC_DLD_M or with Ed. 2.1 MOlnNs): "The attribute shall be present, if LN name space of this LN deviates from the LN name space referenced by ldNs of the logical device in which this LN is contained (applies to
lnNs in CDC LPL only).".
This means that if the namespace of the LN (lnNs) differs from the one of the LD (ldNs), then NamPlt.lnNs is mandatory, otherwise it is optional.
There is in contradiction with Part 7-1, Clause 13.4.3, where it is written: "The attribute shall only be available in a LN instance if its value differs from the ldNs value."
This would mean that lnNs is forbidden if it would be the same as the one of the logical device (and not optional as defined in 7-3).
The same contradiction can be found in 7-1, Clause 13.4.3 for dataNs.
Modify the sentence in 7-1 Clause 13.4.3 as follows:
"The attribute shall be available in an LN instance if its value differs from the ldNs value. The attribute is optional in case the lnNs and ldNs values would be the same."