Australia: Short Paid Aerogramme

Australia aerogramme (Stein #A-40) sent from HOBART (4 NOV 1974) to Finland. The aerogramme contained an enclosure and was therefore treated as a short paid air mail letter (16 c deficiency).
 
Red oval instructional handstamp “AUSTRALIAN POST OFFICE / POSTAGE DEFICIENCY / ADJUSTED / HOBART MAIL EXCHANGE”.
 
A new  "honor'' system was  introduced  on  a  trial  basis  at  the Mail  Exchange  Branch  on  February 1, 1972,  for  collecting  deficient postage  on  unpaid  or  underpaid  mail  for  overseas  destinations. Underpaid  air  mail  letters  were  held  at  the  office  of  posting  for  a few days  while  the  sender  was  informed by an underpaid collection card and requested  to  make  good  the shortfall.


Reference:
Stein, The Aerogrammes of Australia and Its Dependencies, 1944-1980

Credits:
Thank you, Allan, for explaining to me the "honor" system of collecting postage due.