To answer your questions.
The first is a paypal issue, that is how paypal works with carts that have invoice numbers or cart ids. They cache that information and it releases over like 10 minutes or so, this is not something we can control.
The second it because of a reason. thirty bees rounds prices to 6 zeros. So when you have a product that costs $1 and a 33% discount, the price is actually .666666. The reason being is some currencies have little value compared to others, think yen to euro. So it helps with conversion. Paypal also has their own rounding algo as well, it just works off 2 decimal places. We removed sending discount and voucher amounts to paypal because they would display the wrong amounts from what the cart displays.
The third does this happen immediately? or have you given time for the paypal cookie to die, like 30 minutes or so?