Check the contract terms to see if they are Fixed Price. The invoice creation wizard does not include fixed price time/cost. Make sure you look at the actual contract terms and not the engagement type. Sometimes people change the terms, but forget to change the type. This causes a situation where your type is "T&M," but the terms are actually Fixed Price.
If you have fixed price cost cards, they do need to be pulled into an invoice eventually. See How to clear deferred revenue on fixed price cost contracts.