Business Day count

Can anyone tell me how to correct the program below so the consecutive days continue to add up even if the month changes?

 

Shared NumberVar consecDays;
Shared NumberVar consecDaysMax;

if(Previous({TR_CC_HRIS_MAND_ABS_BY_SUPVID.TR_GEMS_ID}) = {TR_CC_HRIS_MAND_ABS_BY_SUPVID.TR_GEMS_ID} and
   DateDiff("d",Previous({TR_CC_HRIS_MAND_ABS_BY_SUPVID.RETURN_DT}), {TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT}) <= 1 or
   (DateDiff("d",Previous({TR_CC_HRIS_MAND_ABS_BY_SUPVID.RETURN_DT}), {TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT}) = 2 and
    DayofWeek(DateAdd("d",-1,{TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT})) in [1,7] and
    DayofWeek(DateAdd("d",-2,{TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT})) in [1,7])) then
    consecDays:= consecDays + DateDiff("d",{TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT},{TR_CC_HRIS_MAND_ABS_BY_SUPVID.RETURN_DT})
else
    consecDays:= DateDiff("d",{TR_CC_HRIS_MAND_ABS_BY_SUPVID.BEGIN_DT},{TR_CC_HRIS_MAND_ABS_BY_SUPVID.RETURN_DT});

if(Previous({TR_CC_HRIS_MAND_ABS_BY_SUPVID.TR_GEMS_ID}) <> {TR_CC_HRIS_MAND_ABS_BY_SUPVID.TR_GEMS_ID}) then
    consecDaysMax := consecDays
else if(consecDaysMax < consecDays) then
    consecDaysMax := consecDays;

consecDays