When calculating your service hours, use hours and tenths of an hour. Always round up to the nearest tenth. Time increments in tenths: 6 min = .1, 12 min = .2, 18 min = .3, 24 min = .4, 30 min = .5, 36 min = .6, 42 min = .7, 48 min = .8, 54 min = .9, 60 min = 1.0