(b) Each state agency adopting or proposing adoption of a model code, national standard, or specification shall adopt or propose adoption of the most recent editions of the model codes, as amended or proposed to be amended by the adopting agency, within one year after the date of publication of the model codes, national standards, or specifications. The “date of publication of a model code, national standard, or specification” is either of the following:

1. (1) The date of publication printed in the model code, national standard, or specification. If only a month and year are shown by the model code, national standard, or specification adopting agency or body, the date of publication shall be considered to be the last day of the month shown.
2. (2) The date determined by the commission, if no publication date is shown in the model code, national standard, or specification. The commission shall notify all adopting agencies of its determination within 15 days.