An issue occured when you added your own product with a fix price.
When you manually change the price, it shows correctly on the web preview but when you download the pdf generated through the web-preview, it show the original prices
you can view this here, please use discression, these are actual live invoices
it seems like it cache’s the fixed prices.
I created the PDF from inside the system then went back and generated it from the guest pdf and then it gave me the proper results
Try to save the invoice again. Normally all amounts will be re-calculated on save.