calibre_convert - Renaming e-books

I have been using Calibre for years now.
I mostly use it to convert different types of ebooks into epub or re-save an epub after editing the metadatas.
I do not use it as a library organizer. I'm used to organize it myself.

Now I run Calibre 2.76 on an Ubuntu 16.04 system.

The way I organise my eBooks on my reader is as folow:

-Type of litterature (thrillers, sf, fantasy etc...)
-Author
-File: Author - Serie (if applicable) - Title.epub

I went into Calibre parameters and changed the out format to :

{authors}/{title}/{authors} - {series} {series_index:| - | - }{title}

If I wish to convert a mobi file to epub for instance :

Leon Dwirpoe - Fritzmooch in Merblexland 01 - Fritzmooch gets it.mobi

I expect to get a:

Leon Dwirpoe - Fritzmooch in Merblexland 01 - Fritzmooch gets it.epub

Instead I keep getting a:

Fritzmooch gets it - Leon Dwirpoe.epub

This is not much of a problem if it's only one book, but if the serie has 43 volumes
it's a bit of a drag to have to rename every file one by one.

Anybody has a clue on what I do wrong ?