We base our invoice on the total minutes of your transferred footage. For slides or images, it is based on the actual number of images. Therefore, it is only after the transfer is completed that we will know the total cost of your order. We then notify you via email, and that's when you pay for your order.
If you have under-estimated your total footage (or slides), your invoice will be a bit more, and if you have over-estimated, then the cost will be a bit less.
More information about our order process