Need Start and stop times for individual Payroll time types in fast formula

Content

Hi I am trying to use time calculation fast formula to process meal logic to subtract meal hours from the regular hours. Now I am using the existing fast formula but I am stuck at point .

We have following design

Payroll time type  Start time stop time

Regular Hours    08:00 AM   08:00 PM

Meal Break          10:00 AM 10:30 AM

Meal Break           04:00 PM  04:30 PM

INPUTS ARE  
  HWM_CTXARY_RECORD_POSITIONS,
  HWM_CTXARY_HWM_MEASURE_DAY,
  measure ,
  OraMeasureAll ,
  UnitOfMeasure ,
  PayrollTimeType,
  StartTime,
  StopTime,
  TimeRecordType 

nidx = 0    
WHILE (nidx < max_ary ) LOOP 
(  
    nidx = nidx + 1 
 
 l_rec_pos = NullText
 l_measure = 0 
 l_OraMeasureAll = 0
 l_UnitOfMeasure = NullText
 
 l_measureDay = 0
    l_tc_StartTime = NullDate