It is an issue with local CALCULATED postage.

I use Flat price for international, and then exclude countries I don't post to. Which I set up once in my preferences and comprise all countries except Australia.

All that stuff is in my basic templates, so I should only have to change it for non-500g satchels. Unfortunately, I have to go 'flat rate' and back to calculated to get metric measures, and then have to fill the weights and measurements in again.

Still better than using SYI as I do my listings in advance of when they go live.