(a) The charges to electric plant, operating expense and other accounts for services and expenses of employees engaged in activities chargeable to various accounts, such as construction and operations (or in more than one type of electric operation, such as production and distribution) shall be based upon the actual time engaged in the respective classes of work, or, in case that method is impracticable, upon the basis of a study of the time actually engaged during a representative period.

(b) The pay and expenses of general officers shall be charged to the actual work on which they are engaged, to the particular operations over which they have direct supervision, or, if their jurisdiction is over the entire electric operation, to the appropriate accounts provided in the Administrative and General group in operating expenses.

(c) Except as otherwise specifically provided in this system of accounts or by order of the commission, no amounts for salaries or wages shall be included in charges to electric plant, cost of removal, or electric operating expenses, except employees' welfare and pension expenses includible in account 1800, Other General Expenses, which are not paid to employees affected subject to their free disposition. Payroll deductions made under a statute or order of a court; or for such purposes as group insurance, purchase of appliances or homes, etc., authorized by written order of the employee without coercion of any kind, may be included.