Australia To Brazil Taxed Cover 1947 Or 1948

I have recently purchased the cover here.

Working out the deficiency is straight-forward. From May 1947 until 1952, the airmail rate to Brazil was 2'3 (up from the previous rate of 1'8). The letter is short-paid 6d.

A double-deficiency of 1s applies and this is converted to 80 centimes at a conversion rate of 1d = 6#8532; centimes which applied from 1 July, 1940 to mid 1948.

The Brazilian conversion from 80 centimes to 4 cruzeiros 80 centavos is at 1 centime = 6 centavos.

So, my question is about the use of normal Brazilian stamps for the collection of the amount due, rather than specific postage due adhesives. Why was it done this way?

I would also appreciate some help in identifying the Brazilian cancel.

Guess:
There were no dedicated postage due emissions after 1949
Prev Stocks depleted?

... and what is that "squared circle Pmk on the Kookaburra

Brazil Pmk too faint to read.

Rod,

I can only make out the "OC 7" in the cancel. The taxing treatment would have to make it OC 7 1947, it had changed by OC 7 1948.

Interestingly, the tax mark is Victorian, not a South Australian one. I presume this was because the item left the country from Melbourne, not Adelaide.


John

John,
you always manage to confuse me.
Why on earth would it have been South Australian?

The Brazil Pmk has an "S" so cannot be Rio De Janeiro

I thought I recalled a Brazilian "Surcusal" ? meaning regional
but dashed if I could find it in my records, that really irritated me.
If anyone recalls "surcusal" please put me out of my misery/

What is the blue line smudge and the whitened out scribble I wonder.

The cancel on the Australian adhesives is a squared circle.

The scribble reads "To America to Brazil".

So South Australia was the only state with Squared Circles?
I have learnt something today.

If I were Postmaster, I would sack that clerk.
Can he not ink the hammer?

and the CX ??? that refer to the taxation catalogue ref?

SURCUSAL = Spanish Branch Office