Graduated Rate Schedules

Many financial operations involve tables of rates and values, e.g. US Federal Income Tax, Social Security Withholding, and business discount and commission schedules. In the Options dialog, there is a button captioned Grad Rates which allowed editing the 8 graduated rate schedules.

This is what the Grad Rate dialog looks like:

Each of the 8 graduated rate schedules can have up to 10 brackets, if you donít need all 10, just leave the ceiling blank. The last bracket also has a blank ceiling which means that its bracket applies to all values from there up. The floor of each bracket is the ceiling of the previous bracket, the floor of the first bracket is a very large negative number, so if you enter a negative value in the example above, you will get back a value of 0 because the first bracketís percentage is 0 and any value below 10000, including all negative values will have a rate of 0 applied. The ceiling of the last bracket can either be explicitly entered, in which case, all values above that are 0%, or left blank, in which case all large values have the last bracketís percentage applied. In the US, Social Security withholding has a maximum bracket ceiling, but Federal Income Tax doesnít.

You can enter negative percentages and ceilings if you can come up with a use for them. For negative amounts entered, the value is based on the sum of the amounts from all the negative brackets up to a value of zero. For positive amounts, the value is from zero up to the amount.

Bracket ceilings must be in ascending order

All the Graduated Rate Functions

GRVal
	GRVal(which, amount)
	which: index of grad rate def
	Sums brackets up to amount's
	and calcs amount in top bracket
	Uses entries in Grad Rates in Options
GRMax
	GRMax(which, amount)
	Ý= value from max bracket
	which: index of grad rate def
	Uses max bracket's percent on amount
	Uses entries in Grad Rates in Options
GRPct
	GRPct(which, amount)
	Ý= percent of bracket
	which: index of grad rate def
	Amount is bracket, returns it's percent
	Uses entries in Grad Rates in Options
GRCl
	GRCl(which, amount)
	Ý= ceiling of bracket
	which: index of grad rate def
	amount: selects bracket
	Uses entries in Grad Rates in Options
GRFl
	GRFl(which, amount)
	Ý= floor of bracket
	which: index of grad rate def
	amount: selects bracket
	Uses entries in Grad Rates in Options