User wants to hide the sub-phases of a project on an invoice. Even though the sub-phases are to be hidden, the total amount should feed into the phase as normal. Is this possible in CORE?

Unfortunately, the current phased invoice template in CORE doesn't allow this. Each phase and sub-phase is shown on the invoices. If this is a feature you need, you can consult with the Custom Reports Team at customreports@bqe.com for a custom invoice.