Verification schedules should get triggered as per the schedule window set. There shouldn't be any issue here.
Verification schedule is handled by the SC server windows task scheduler while the SQL backup schedules are handled by the Plugin Host windows task scheduler. Please check the server time setting difference if any.
'deferred backup number in the verification schedule' is the number of backups you would like to get verified when the verification schedule kicks in.
For Ex: If your backup runs every hour and verification schedule is set to 5hr 30 mins window, by the time verification schedule runs you would have 5 backups already. You can specify how many backups you need to verify by setting this number.