The OP has things mixed up quite a bit. For starters, Point Of Sale flow should be described separately from the Card Not Present (as in online purchases) flow

The OP has things mixed up quite a bit. For starters, Point Of Sale flow should be described separately from the Card Not Present (as in online purchases) flow (protip there really is no such thing as transaction void in POS world). There are also things like auth reversals, partial captures etc.