@Andrew142
"Do I need to change it from Parts to something else then back again? It seems that there would be an easy to do this."
Making changes to invoices has no affect on invoices with non-inventory items on them. Non-inventory items are expensed when purchased, so you need to change the bills used to purchase the items or create a journal entry that debits COGS and credits the GL account(s) that were used on the incorrectly-coded items.
