Hi densitylabs ,
Thank you very much for another great post.
You are right, it could be a long way to handle multiple currencies manually. However, the free ATUM is not build for these kinds of business scenarios. Supplier details are only informational and the currency have no effect on POs.
Handling this scenario is planned to go premium as well, but not earlier than mid to end of 2020.
Reading all your posts, even though is really hard to say this, but you may have to look for more advanced system to manage your business. ATUM is evolving, but it will take some time to successfully satisfy all users.
Hope this makes sense.