The city, borough, incorporated town or township as employer shall, in all cases, be deemed to have knowledge of all other employment of all auxiliary police, including self employment, and earnings in such employment shall be included in computing average weekly wages. In all cases where an injury compensable under the provisions of this act is received by an auxiliary policeman who is, in whole or in part, a self employer and loss of earnings results therefrom, such earnings shall for the purposes of this act be regarded as wages. The average weekly wage as so regarded shall be that most favorable to the employe computed by dividing by thirteen the total earnings of the employe in the first, second, third or fourth period of thirteen consecutive calendar weeks in the fifty-two weeks immediately preceding the accident. In all cases where an injury compensable under the provisions of this act is received by a member of the auxiliary police who is self-employed or unemployed, payments shall be made of not less than twenty-two dollars and fifty cents ($22.50) per week for total disability and not less than twelve dollars and fifty cents ($12.50) for partial disability.