Nothing has been published as far as we are aware. The PSSC is designed to be a simple, straightforward contract for low-risk, straightforward commissions. It is therefore not a case of missing out things from the PSC, but more a case of simplifying matters to make them easier to deal with, or on occasions, making them optional.
Examples of the former can be found in the processes for early warnings, payments and compensation events. An example of the latter is the programming requirements, which are left to the employer to specify in the contract data. Further simplification has been achieved by removing main and secondary options and making it more of a one-size-fits-all approach.
We suggest you read the two contracts together and these matters will become clearer. They both have the same layout, with the same nine sections dealing with the same matters in the same order, so you can easily compare them section by section. Both contracts are of course written in the same plain English.