Then we could populate a drop-down, one of the addresses can be set as default, and the store can be an option.
#2, not sure what you're asking, what's wrong with the current display? I think the main thing is we need the rate, the basis, the location code, and probably the taxing authority. I don't know that there can be different rates within the same order (same destination) -- as far as I'm aware, there are not different rates for different kinds of products -- but if there are it might be necessary to have multiple tax lines. One consideration is whether shipping/handling is taxable or not...Hmmm Reading SSUTA it looks like at least two rates are allowed for each jurisdiction (food/drugs and everything else). But there are also lots of other unknowns. For example, states may define what constitutes taxable shipping and handling, or whether clothing is taxable based on how much it costs (a state-set threshold), or whether insulin is taxed under food and drugs or prescriptions (even if it requires a prescription). So one huge issue is that there are products which may clearly cross categories when crossing states. I don't know how to handle that. But that's just my cursory reading through the 200 pages of regulation.The rounding rules, we can handle. It looks like we can round the tax per item or per invoice. I would recommend per item.