Considering that during the Songkran week nothing happend, I think today is the 10th business day since your application (not counting the day of application). Cambodia normally issues the visa exactly 10 (or actually 11) business days after the application. And mine came after hours, pretty late in the evening. Just give them a 1 or 2 more days before you get nervous!
, not exactly. You pay taxes in the country you're a tax resident in. Or, if you're from the US or Ethiopia, you pay taxes based on nationality. There is a whole "science" around this. Google Perpetual Traveller+taxes if you want to learn more about how it's done.