Sampling Plans for Pharmaceuticals Raw Materials

Since WHO published a guideline for pharmaceuticals raw material sampling plan, which comprises of n-plan, p-plan and r-plan, but it also mentions “It should be noted that sampling plans are not recommended for sampling of starting materials
for identification tests” in the starting paragraph.

Then I dont understand what it is actually for then.

But what i wanna ask,
we know that it is ideally to sample and test every containers of pharmaceuticals raw materials for identity.
But is there any recognized sampling plan to reduce sampling size, is r-plan feasible?
e.g. where there is an entry of 200+ bags of sugar or API.

Sampling plans and procedures must be statistically valid and should be based on
scientifcally sound sampling practices taking into account the risk associated with the
acceptance of the defective product based on predetermined classifcation of defects,
criticality of the material, and past quality history of the vendor. In some circumstances,
such as for large number of containers, a sampling plan based on (√n+1) may be
acceptable. However, a sampling plan based on ( √n+1) may present a signifcant risk of
accepting defective goods in certain circumstances, such as the sampling of a small
number of containers. As with all sampling plans, documented justifcation must be
available. (Health Canada)