Pricing on invoices

Hi everyone,
I’m hoping someone can help us. We have recently started using square and our only problem is that when entering invoices on the computer we cannot alter the set item price for our customers. We have many customers, some with different prices for certain products and we also price match so need to be able to do this. For some reason you can’t alter it which seems ridiculous to me as you can on the POS without any problems. It’s also not viable to set every product with a variable price as we have thousands of products that we need to be able to reference.
Thanks so much for any ideas/ help.

Hey @TWFsydney! Just to make sure I’m on the same page here, are you doing this via a custom coded application with Invoices API, or are you using the Invoices section of the Square Seller Dashboard?