Will the automatic import of residues be carried out if there were no changes in the import xls file?

Question

1C-Bitrix

There was a task to put the supplier on automatic updating on prices and balances. The supplier sends a price list by mail quite rarely (once every one or two months). Set up import from email address. But there's a problem. We need to reset the balances at night and then do the import. In this connection, the question is - if the new import is put in crowns, will there be a daily update even if the supplier has not sent a fresh price list to the mail? If not, how can I force the last leftovers to be imported?