I keep looking this up so thought I would clearly document it for myself and the rest of the interweb.

When troubleshooting Configuration Manager Maintenance Windows the runtime number in the ServiceWindowManager.log is in seconds OnIsServiceWindowAvailable called with: Runtime:6600, Type:2 6600/60 = 110 minutes

(6600/60)/60 = 1.83 hours, Or 1 hour and 50 minutes

See https://msdn.microsoft.com/library/jj155419.aspx