Accept total_files in FileBased splitting.

I am just curious how this work.
What does the totalFiles mean? Is this something different from  file_load_limit?
https://github.com/AndresTanasijczuk/WMCore/blob/totalunits/src/python/WMCore/JobSplitting/JobFactory.py#L88

And is there a reason sorting is by lfn? (I guess this is related)