(1) Only those affected local government units which have requested a 30-day extension of the initial review period pursuant to 90-6-307(6) , MCA, may file objections to the plan during this extension. However, if an objection filed during this extension relates to the interests of a local government unit which did not request an extension, that unit will be allowed to comment on the objection, and any such comment may be considered by the board in subsequent proceedings concerning the objection.