To maintain uniformity of accounting, utilities shall submit questions of doubtful interpretation to the commission for consideration and decision. Utilities shall also ask for instructions, if occasion arises, regarding the accounting for such transactions as spreading over a number of months relatively large income or expense items which if included in the accounts for a single month would seriously distort the accounts; the disposition of items which relate to transactions which occurred prior to the current calendar year but which were not recorded in the books of account in the prior year and which are relatively so large that inclusion in the accounts for a single year would seriously distort the accounts; and expenditures for replacement of units of property leased from others. Ordinary delayed items shall be charged or credited to the same accounts which would have been charged or credited if the items had not been delayed.