Since we are into suggestions and improvements, please add an address validation when the user starts mixing. I can leave all addresses field empty and the mixer will still proceed as usual. This means that if the user misstype his address, press an extra character or just forgets to input it, he won’t receive anything from the mixer,

That is a major issue. I’m not attacking you, I’m just pointing out a major flaw that could result in a lot of money lost from your customers. I would say this is an urgent matter and that you should fix it immediately after reading this.