There is an HIPAA Interpretation Request (HIR) on the X12N Web Portal Website. Item 163 on this topic. At this time, the time, effort and cost does not bear the need for an addenda. Portal url:http://www.x12n.org/portal/
"Question: Page 73 of 004010X061 specifies a value of "65" in ENT03 to indicate the National Employer Identifier is contained in ENT04. A value of "65" is not contained in Data Element 66 in version 004010 ... or version 005010 for that matter. What value should be used in ENT03? [Note: Some untraceable sources at this time have stated to use a value of "24" in ENT03; however, "24" is not listed as a valid value in the referenced IG.]
We recognize that we have a technical error, where the Implementation Guide requires the use code 65 once the National Employer Identifier is adopted. But, code 65 was never added to the standard. Consequently, use of the code 65 is not permissible, without violating the standard.
Since the standard and the Implementation Guide both support code FI, we recommend that as a work around solution, code FI should be used to identify the new National Employer Identifier. This is not all that illogical, since FI is the code for the Employer Tax Identifier, and as it turns out the National Employer Identifier is also the Federal Tax Identifier."