Exponentcms Exponent CMS → 2.3.1

Several things that don't seem to be working as expected or the logic is puzzling (at least in the pre-2.3.1 code)

• how is 'in stock' or 'out of stock' determined? How do we deal with the 'quantity' setting of a product.
• we don't seem to estimate shipping cost very well or at all (non-US only?)
• we don't see to estimate or calculate tax very well or at all (non-US only?)
• we display all shipping options even when a specific shipping option is required, PLUS the highlighting for active/available shipping tabs seems to be backwards
• we display 'table based shipping' or 'flat rate shipping' as the shipping type which means nothing to a customer, where-as UPS or FedEx mean something and we can set 'Free' shipping title.