[Duplicity-talk] Duplicity doubt regarding incremental backups

[NoPlanB]

Dear all,

I am using duplicity since a couple of days and it is working fine so 
far but I have one question regarding the incremental backups.
The backup will be initiated every day via cronjob as follows:

duplicity remove-older-than 1D --force $target
duplicity remove-all-inc-of-but-n-full 1 --force $target
duplicity cleanup --force $target
duplicity $source $target

As you can see I want to have only one backup without any incrementals.
My doubt is that every day when the cronjob is running it is placing an 
incremental backup to my FTP target even if the source has not been 
changed.
In general it is no problem but why duplicity is generating an 
incremental backup file if the source has not been changed?
It does not make sense for me because the target will be flooded with 
hundreds of files after a couple of months.
Furthermore why it is not possible to delete the older inc files? It 
says always to me that "....Which can't be deleted because newer sets 
depend on them".
Also here I cannot understand why there is a dependency if the source 
has not been changed.

Many thanks for your support!

Kind regards, Kai