1. If, prior to the letting date of the construction project, the commission's project plan is changed so that additional or different utility relocation work is found necessary, the commission shall furnish a revised project plan under section 227.554, and the owner shall provide the commission with a revised relocation plan under section 227.555, except that the time allowed for the owner to submit the revised relocation plan after receipt of the revised project plan shall not exceed sixty days.
2. If, after the letting date of the highway construction project, additional utility relocation work is found necessary which was not indicated on the original project plan, the commission shall provide the owner with a revised project plan within fifteen days and the commission and the owner shall agree on a reasonable schedule for completion of the additional utility location.