Backup and Recovery

In researching ways of fixing the full calendar folder discussed in 
another thread, I have a couple of questions to which I can't find 
answers in the archives:

 1. In File > Properties > Backups, I would have expected I could
    specify 9 local backups, but it does not seem to accept any more
    than 8 -- anyone know why that is so?
 2. Ecco Help has a very scanty description of recovery -- if I do file
     > Database > Recover and the result is "Ecco was unable to recover
    data from the file", does that mean that everything is OK?
 3. Back in 2013, r634718 said "if you use EccoPro Extension, it has a
    superb daily backup feature that can make a backup copy of the last
    version of your file each day and save them for a user selected
    number of days" -- where can I find that feature?

Thanks in advance.

Lindsay Graham
Canberra, Australia