CA Service Management

We have different service levels(like level 1,2 etc) and there are mapped to different workshift(like regular,24X7 ect).For various time calculation such as response time and resolution time , we need to feed this workshift in to spell.Please let us know how we can implement this one.    

Not sure if this is what you need, but this is example how to get workshift information by ID and use it to calculate duration between two dates

send_wait(0,top_object(),"call_attr","wrkshft","sync_fetch","DYNAMIC",format("persistent_id = 'wrkshft:4600'"),-1,0);
   if (msg_error()) {
    logf(ERROR, "Update object macro error: %s, Incident %d", msg[0], ref_num);
   }
  int wrkfound;
  object wrkList,wrkPointer;
  wrkList = msg[0];
  wrkfound = msg[1];
  if (wrkfound > 0)
  {
   send_wait(0, wrkList, "dob_by_index", "DEFAULT",0, 0);
    if (msg_error())
    {
     logf(ERROR, format("AHDConnect:dob_by_index %s, Incident %d", msg[0], ref_num));
     return (-4);
    }
    wrkPointer=msg[0];
  }

string business_hours;
business_hours = wrkPointer.sched;
newDuration = workshift_abs2work(business_hours, open_date, last_mod_dt);