I want to make a small change in the formula

Hi friends,

I found this formula in marketcalls. In this formul daily , weekly and mountly.How can add 2 days and 3 days in this formul.

_SECTION_BEGIN("Price");
SetChartOptions(0,chartShowArrows|chartShowDates);
_N(Title = StrFormat("{{NAME}} - {{INTERVAL}} {{DATE}} Open %g, Hi %g, Lo %g, Close %g (%.1f%%) {{VALUES}}", O, H, L, C, SelectedValue( ROC( C, 1 ) ) ));
Plot( C, "Close", ParamColor("Color", colorDefault ), styleNoTitle | ParamStyle("Style") | GetPriceStyle() );
_SECTION_END();

_SECTION_BEGIN("VWAP");

function Lastthursday()
{
Daysinmonth = IIf( Month() == 1 OR Month() == 3 OR Month() == 5 OR Month() == 7 OR Month() == 8 OR Month() == 10 OR Month() == 12, 31, 30 );
Daysinmonthfeb = IIf( Year() % 4 == 0 AND Year() % 100 != 0, 29, 28 );
Daysinmonthfinal = IIf( Month() == 2, Daysinmonthfeb, Daysinmonth );
returnvalue = IIf( Daysinmonthfinal - Day() < 7 AND DayOfWeek() == 4, 1, IIf( Daysinmonthfinal - Day() < 8 AND DayOfWeek() == 3 AND Ref( DayOfWeek(), 1 ) != 4 AND Day() != Daysinmonthfinal , 1, 0 ) );
return returnvalue;
}

Period = ParamList( "Base", "Daily|Weekly|Monthly|Lastthursday|Yearly", 1 );



if(Period=="Daily" )
{
Bars_so_far_today = 1 + BarsSince( Day() != Ref(Day(), -1));
StartBar = ValueWhen(TimeNum() == 091500, BarIndex());
TodayVolume = Sum(V,Bars_so_far_today);
average = (H+L+C)/3;
IIf (BarIndex() >= StartBar, VWAP = Sum (average * V, Bars_so_far_today ) / TodayVolume,0);
}

if(Period=="Weekly" OR Interval()==24 * 3600 )
{
Bars_so_far_today = 1 + BarsSince(DayOfWeek() < Ref( DayOfWeek(), -1 ));
StartBar = ValueWhen(TimeNum() == 091500, BarIndex());
Vol = TimeFrameGetPrice("V", inWeekly, 0);
TodayVolume = Sum(Vol,Bars_so_far_today);
average = (H+L+C)/3;
IIf (BarIndex() >= StartBar, VWAP = Sum (average * Vol, Bars_so_far_today ) / TodayVolume,0);
}

if(Period=="Monthly" )
{
Bars_so_far_today = 1 + BarsSince(Month() != Ref(Month(), -1));
Vol = TimeFrameGetPrice("V", inMonthly, 0);
StartBar = ValueWhen(TimeNum() == 091500, BarIndex());
TodayVolume = Sum(Vol,Bars_so_far_today);
average = (H+L+C)/3;
IIf (BarIndex() >= StartBar, VWAP = Sum (average * Vol, Bars_so_far_today ) / TodayVolume,0);
}

Plot (VWAP, "Vwap",colorYellow);
_SECTION_END();