It's as per CAO 48 definition with an allowable error of -/+ 3 minutes as .1 of an hour is 6 mins.So 9mins is .1 and 10 mins is .2 etc.And as it's a LEGAL requirement to carry a TIMEPIECE (not mobile phone digital time read-out) measuring hours/minutes/seconds under CAO20.18.Hopefully we can all read the time!!Any other interpretation of this by operators is ILLEGAL.