Charging interest to defaulters

You should search for "reminder" in this community ;) I would like to link to it, but i don't know if that will work.

So if I understand correctly, send a reminder (via Dexxter or whatever), the customer pays it and that's just fine? No extra turnover because it's more like compensation than income.

This also corresponds with what I can find online about the topic, but that seems to match what I read when I search this community!