I lost my final Invisalign tray.My dentist he said it was fine and he would have my retainer made to match the 2nd to last tray.

Lost my final tray and dentist said he would have retainer match the 2nd to last tray. When I asked if not wearing the last tray would effect my treatment or my bite he said no. Is this correct? It doesn't make Sense to me not to finish out the last tray.have read online that ordering a replacement may be free. When I asked my dentist if not wearing the final tray and having my retainer match the second.