Hello,
Since the backups are essential for saving all our data, I tried to understand the working of it in particular with the archiving it to to prevent it from overwritten.
I've conducted some tests and arrived at the conclusion:
The only way to know if the latest backup has been archived or not is to observe the next backup operation.
If the precedent backup has been archived the following backup will take a lenghty time since it is making a backup from scratch; if the precedent backup has not been archived, the following backup will zip thru since it will be an incremental one.
Now I have the rest of mind when dealing with backup and archive.
Thank you everyone.