You have to create New Blank Chart but not New Default Chart. Default chart will have same ChartID for all chart tabs and so if you change Param* it will be changed for all charts to same value. If you create Blank Chart then Param will remain fix per chart tab once it is set and not being modified per chart.
If you look for fix values per interval then use Interval() function.
switch ( Interval(2) ) {
case "Monthly":
no = 20; break;
case "Quarterly":
no = 15; break;
case "Yearly":
no = 3; break;
case "Daily":
default:
no = 25; break;
}
printf( "no: %g", no);
res=HHV(H,no);
sup=LLV(L,no);
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