Credit card interest calculation

[Mit]

Hi SASusers

I have need to do a credit card interest calculation for the number of months the offer is valid.

Thanks

Here is the input data

card	offer	max mnths	rate	opening_balance	days	min_pct_due
A	2.9% for 12 months	12	0.000079	11000	30	0.025
B	1.9% for 6 months	6	0.000052	5000	30	0.025

Here is the output data

card	offer	rate	min_pct_due	Month	Days	Opening Balance	Interest	Closing Balance	Minimum Due
A	2.9% for 12 months	0.000079	0.025	1	30	11,000	27	11,027	277
A	2.9% for 12 months	0.000079	0.025	2	30	10,750	26	10,776	270
A	2.9% for 12 months	0.000079	0.025	3	30	10,506	25	10,531	264
A	2.9% for 12 months	0.000079	0.025	4	30	10,267	25	10,291	258
A	2.9% for 12 months	0.000079	0.025	5	30	10,033	24	10,057	252
A	2.9% for 12 months	0.000079	0.025	6	30	9,805	24	9,829	247
A	2.9% for 12 months	0.000079	0.025	7	30	9,582	23	9,605	241
A	2.9% for 12 months	0.000079	0.025	8	30	9,364	23	9,387	236
A	2.9% for 12 months	0.000079	0.025	9	30	9,151	22	9,173	230
A	2.9% for 12 months	0.000079	0.025	10	30	8,943	22	8,964	225
A	2.9% for 12 months	0.000079	0.025	11	30	8,739	21	8,760	220
A	2.9% for 12 months	0.000079	0.025	12	30	8,540	21	8,561	215
A	2.9% for 12 months	0.000079	0.025	13	30	8,346	20	8,366	210
A	2.9% for 12 months	0.000079	0.025	14	30	8,156	20	8,176	205
A	2.9% for 12 months	0.000079	0.025	15	30	7,970	19	7,990	201
B	1.9% for 6 months	0.000052	0.025	1	30	5000	8	5,008	126
B	1.9% for 6 months	0.000052	0.025	2	30	4882	8	4889	123
B	1.9% for 6 months	0.000052	0.025	3	30	4766	7	4773	120
B	1.9% for 6 months	0.000052	0.025	4	30	4653	7	4660	118
B	1.9% for 6 months	0.000052	0.025	5	30	4543	7	4550	115
B	1.9% for 6 months	0.000052	0.025	6	30	4435	7	4442	112

[Mit]

Hi SASusers

I have sort of figured it out.

proc sort data=have;
by card offer;

data want;
set have
by  card Offer;
count=0;
do i=1 to 15 until (count=max_months);
  interest_promo='Opening Balance'n*Rate*days;

  'Closing Balance'n='Opening Balance'n + interest_promo;
  min_due='Closing Balance'n*min_pct_due;
'Opening Balance'n='Closing Balance'n-min_due;
count+1;
output;
end;
run;

But there is a small problem...

my output starts from the value  of Opening balance=10,750 instead of the starting value of 11000