Collective bargaining agreement (CBA) formula and pre-approved plan document

Does anyone know if there is an IRS Revenue Procedure that requires cycle 3 DC plans and Cycle 2 403b plans to hard code the CBA language into the plan document? I know it is in the pre-approved document but trying to find a cite as to why it has to be. Appreciate any insight. Thanks!

are you talking about a formula? for example if the CBA says a fixed 10% contribution? 

Having that written into the plan document seems standard? If that is what the CBA calls for? then all the plan information - such as summary plan description - includes it correctly. 

Or are you talking about more general CBA language in something like the adoption agreement / basic plan document? 

If more general language - well then that's a function of the pre-approved plan document provider's choices. There are lots of different ones out there, and each organization that is submitting one can tailor the language in the document to be as simple or encompassing as they like, as long as the IRS accepts it. For example, pre-approved documents designed for use by one person plans are usually much much simpler and shorter than ones drafted to accommodate maximum flexibility in design and larger employers. 

I am talking about writing the CBA formula, for example a 10% employer contribution, into the plan document, rather than just reference the CBA like you could in cycle 2 DC and cycle 1 403b. Is there any IRS guidance on this change?

Is this query about whether a set of IRS-preapproved documents may, regarding the participants of a collective-bargaining unit, provide an obligated contribution (or describe an intended contribution) by referring to a collective-bargaining agreement (rather than filling in something on an adoption-agreement form)?

I am looking for the IRS requirement that the formula has to be stated in the plan document rather than just referenced? Here is an example below -

Contributions under collective bargaining agreement, employment contract or equivalent arrangement. The Employer will make an Employer Contribution based on a collective bargaining agreement, employment agreement or equivalent arrangement as follows:                                                                                                                                                                                  

[Note: Insert the appropriate contribution formula (and allocation formula, if applicable) from the collective bargaining agreement, employment agreement or equivalent arrangement. The formula must be definitely determinable. Alternatively, the Employer may attach an addendum incorporating the collective bargaining agreement, employment agreement or equivalent arrangement. ] 

Apparently, the IRS informed pre-approved document providers it would not approve Cycle 3 documents if the CBA formula was incorporated by reference.  This approach had been allowed in the PPA cycle documents.  The rationale was the allocation formula had to be in the Cycle 3 document itself or the formula was not considered definitely determinable (i.e., subject to modification if a change was made in the CBA which is outside the control of the plan).

I have not seen an IRS directive to that effect, but I have seen commentary to that effect from pre-approved document providers.

One of the sadnesses of the IRS-preapproved documents regime is that IRS people set conditions on what will get an opinion letter, and often make those interpretations with no rulemaking procedure and even nothing in the Internal Revenue Bulletin.