The Roo Cover post inspired me to look at my Australian covers to see if I could find other examples of high denomination stamps used for postage. I found this one, which is still sealed with only a thin card inside. The denominations add up to 3s 8d (a 2s stamp, and 20d in other stamps). It is a registered cover, sent by air mail to the USA.

Here is what I'm not sure about.

1. is 3 shillings plus, an appropriate rate in 1954 for something this thin, even by registered airmail?

2. The back cover cancels show a departure date of 15 Feb 1954 and an arrival date of Apr 5, 1954; why would it take almost two months to reach the US by airmail?

What do you think?