I knew you quoted XE mid-market rates.
I measure the loss on any foreign currency transaction against that mid-market rate. With the expectation that there always will be a loss.
Something like 0.5% loss would be a very good result, as you might get with Transferwise or even the most competitive cash exchanges.
You don't have a Transferwise option for Cambodia. As stated, I think a 1.3% loss is a very good result for a less competitive market.
For example, compare with the c**** at Paypal, who charge £25 (5.6%) to receive £450 from China & charge the sender something similar on top of this, so over 10%. Transferwise is also not available for outbound transfers from China. I'm fairly sure there is a better option waiting to be discovered.
My UK bank charged 3.2% for an overseas transfer of several thousand pounds, in the days before I discovered Transferwise.