Hello Jackie-bouncetog,
Welcome to the Community page,
If you set up the product and service's and post to two different accounts so if you had one product and service going to one type of income account and then the other product and service going to another type of account in the Chart Of Accounts then they show up in the P&L under those 2 accounts as an invoice only deals with products and services but if its only one type of product and service then you would have to journal X amount out of that service account and post to another account.