Why EagleFiler always created new 'INBOX-{N}' folder?

hi all!
I have mac os leopard, eaglefiler 1.5.5 and Mail.
When I try to import my emails from ‘Mail’ program and press “F1” button then the eaglefiler import emails into INBOX folder. Here all is ok. But, when I press F1 again (with another list of mails) the eaglefiler created another folder with name “INBOX-1” and push all mails to it. If I press F1 again and again then eaglefiler created “INBOX-2”, “INBOX-3”… and so on. Why it is happen? Is it a normal way? I’d like to have only one folder with name “INBOX”.
Thanks for answer.

Yes, this is normal. If you want, you can combine them using the Merge Mailboxes command.