Upper case turns off a given check. Lower case turns it on.
When you turn off a check, maybe, "no checksums", then all subdirectories inherit that: no checksums are done.
You can always override switches that are inherited from parent directories.
e.g., In the example below, all the stuff under /var/log won't have checksums done, except all the files under /var/log/archives:
/var/log S /var/log/archive s
... Again, the upper case turns the check off, and the lower case turns it back on.
|l||number of links|
|z||file size (redundant if checksums are on)|
|c||file info change time (see lstat(2))|
|r||reset access time after checksum (option)|