Moved to Web Gateway for better support.
there are also some samples in the Online Rule Set Library on contentsecurity.mcafee.com, which give some examples how to use the Time and Date functions. Basically all Time and Date functions only define when a rule is triggered or not. They do not depend on trailing rules, but you need to make sure that no rule is executed previously that prevents the rule from being executed. You can easily configure a rule which should match at a specific amount of time and then use the rule engine tracing to find out why the rule is not executed.
If the rule should block access it certainly must be set to "Block".