User is unsure about how to set a specific amount when creating a recurring invoice in the Recurring > Add Recurring Invoice screen.
Recurring invoices formulate the invoice amount based on the source invoice you choose. So, when you are creating a recurring invoice, just provide the correct source invoice in the 'Source Invoice' field. If you don't have any for the relevant invoice amount, then create a new source invoice for it. Check CORE Help Center for details.