Differences between dumpy and tilting level?

in dumpy level the line of sight is perpendicular to vertical axis.But in tilting level the line of sight need not be perpendicular to vertical axis .the instrument is roughly leveled in a tripod stand with respect to bubble tube & thus making the instrument approximately vertical...then it is tilted with a finely pitched tilting screw which tilts the telescope wrt to vertical...it has advantage that due to tilting levelling can be done quickly and accurately!!