Importing Invoices

Hey guys,
I'm still testing this software out. I'm trying to import invoices that I exported from quickbooks. I've got around 400 invoices, but the free version only allows 5 invoices per month. Is there a way I can import all of these or do I need to pay the monthly fee?
If I have to pay the fee, I'd need the $25 per month account just to import all of these, but I realistically only create 25-35 invoices per month. If I have to subscribe at $25 to get my invoices imported, can I go down to the $15 per month plan later?