You didn't indicate what product you are using. If you are using ADP PC/Payroll for Windows with an SQLBase database then create a report with at least Hire Date, Termination Date and Rehire Date from the V_EMPLOYEE view (they can be Query Only if you want) and then create a Derived Field called whatever you want (like LOS) and copy and paste the following into it:
@IF( @INT( @DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) / @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)) ) ,
@IF( @INT( @MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) / @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)) ) ,
@STRING(@YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @YEARNO(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' y ' || @STRING(@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' m ' || @STRING(@DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' d ' ,
@STRING( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @YEARNO(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)) - 1,0) || ' y ' || @STRING(12 + (@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE))),0) || ' m ' || @STRING(@DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' d ' ) ,
@IF( @INT( @MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) / @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)) ) ,
@DECODE(@MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW)),@MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),
@STRING(@YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @YEARNO(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)) - 1,0) || ' y ' || @STRING(12 + (@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)))-1,0) || ' m ' || @STRING( @DECODE(@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - 1,1,31,2,
@IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,4) ,28, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,100) ,29, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,400) ,28,29) ) ),
3,31,4,30,5,31,6,30,7,31,8,31,9,30,10,31,11,30,0,31)+ @DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' d ',
@STRING(@YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @YEARNO(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' y ' || @STRING((@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)))-1,0) || ' m ' || @STRING( @DECODE(@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - 1,1,31,2,
@IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,4) ,28, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,100) ,29, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,400) ,28,29) ) ),
3,31,4,30,5,31,6,30,7,31,8,31,9,30,10,31,11,30,0,31)+ @DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' d '),
@STRING((@YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @YEARNO(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE))) - 1,0) || ' y ' || @STRING(12 + (@MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @MONTH(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)))-1,0) || ' m ' || @STRING(@DECODE( @MONTH( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - 1,1,31,2,
@IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,4) ,28, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,100) ,29, @IF( @MOD( @YEARNO( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) ,400) ,28,29) ) ),
3,31,4,30,5,31,6,30,7,31,8,31,9,30,10,31,11,30,0,31)+ @DAY( @NULLVALUE(REPORTS.V_EMPLOYEE.TERMINATIONDATE, @NOW) ) - @DAY(@NULLVALUE(REPORTS.V_EMPLOYEE.REHIREDATE, REPORTS.V_EMPLOYEE.HIREDATE)),0) || ' d ') )