In regard to the Simpson Grierson opinion
I think they are probably referring to this part of the act
[http://www.legislation.govt.nz/act/public/1986/0005/latest/DLM88273.html]

Commerce Act 1986 No 5 (as at 01 April 2009), Public Act
Part 2 Restrictive trade practices
32 Certain recommendations as to prices for goods and services exempt from application of section 30
Nothing in section 30 of this Act applies to a provision of a contract, arrangement, or understanding, to the extent that the provision recommends or provides for the recommending of the price for, or a discount, allowance, rebate or credit in relation to goods or services where the parties to the contract, or arrangement, or understanding include not less than 50 persons (bodies corporate that are interconnected being counted as a single person) who supply or acquire, in trade, goods or services to which the provision applies.
Compare: Trade Practices Act 1974 (Aust), s 45A(3)

Kensington Swan say this about it:

There is an exception under s 32 for price recommendations where the parties to the arrangement include not less than 50 persons. This exception was intended more for trade associations but could also be of relevance to large franchise groups. However, it would be important that the recommendation be a genuine recommendation and that there be no requirement or pressure to follow the recommended price. (Section 32 exempts certain recommendations as to prices for goods and services from application of s 30. The equivalent section in the Trade Practices Act, s 45A(3), was repealed in 1995.)

http://www.kensingtonswan.com/Publications/Competition%20&%20Consumer/Franchises_and_competition_law.pdf