The Board must ensure that minutes are kept of proceedings at meetings of the Board and that a record is kept of all written resolutions of Directors.
Which is clearly a much lower requirement, allowing discussions to happen un-minuted and information to be hidden. Interestingly, they also modified the standard clause that such minutes are prima facie evidence of proceedings to add "unless they are shown to be inaccurate" - effectively allowing them to repudiate their own decisions.
(You can get all of this from its page at the Companies Office)
As for the reason, its pretty obvious: the Christchurch rebuild is a politically hot topic, and board minutes will be OIA'ed to keep an eye on it. By making them less complete, they deny information to the public about what is planned. The second change also seems to be a deliberate effort to protect against lawsuits, by creating an ability for Board members to perjure themselves. Its a perfect example of how freedom of information (and government accountability) depends on the keeping of accurate public records, and how that is attacked to undermine accountability.
But there's a problem: while its a company, Otakaro is also very clearly, as an agency of both central and local government, a "public office", and subject to the Public Records Act requirement to create and maintain full and accurate records of its affairs. And to the extent that this amendment signals an intent not to do so, I think the Chief Archivist might want to take a look at it...
Meanwhile, it will be interesting to see whether Gerry Brownlee ordered or was informed of this. Because if he did, we have an outright conspiracy against transparency from a senior government Minister.