SUMPRODUCT MATCH INDEX Formula

I would like to write a formula that I believe will be a SUMPRODUCT formula with a very complicated string of MATCH and INDEX (I think). I hope this can be written in one formula - but if I need a couple to get there, that would be okay too. I am modifying an existing workbook that currently does the calculation, but it need a separate sheet for each payment - up to 12, but it can't be easily modified for more, and I need to do about 120. I can do limited SUMPRODUCT formulas and can do some limited MATCH formulas, but I can't begin to figure out how I would string this formula together. Hopefully what I need to do is clear with the excel shot below. If not, I could post a sheet that does the calculation for one payment. Thank you for working any magic you can on this.

I will try to explain how this formula needs to work. The formula needs to calculate interest on a payment, from one date to another date using a set of fixed interest rates that are established for each quarter. So this is what the formula needs to do. The workbook has a table (see below) that identifies the quarter - dates from and to, the number of days in the quarter (may be needed in the formula, but maybe the formula would calcualte?) The first and last quarter would most likely not be applied for the full number of days, since the payment would be after the start of a quarter, and the end date may not be at the end of the quarter. It needs to determine if the payment falls in a quarter, how many days then are in that quarter, and apply the base dollar amount for the number of days at the daily interest rate. So it would need to look at all dates and do this calculation and add each of the quarters together until it gets to the "Calculate to date" (cell J5). In the sheet below, I would put the formulas for each paymant in cells K8 to K14.

******** ******************** ************************************************************************>Microsoft Excel - Test.xls___Running: 11.0 : OS = Windows XP (F)ile (E)dit (V)iew (I)nsert (O)ptions (T)ools (D)ata (W)indow (H)elp (A)boutD5F5D6F6D7F7D8F8D10F10D11F11D12F12D13F13D15F15D16F16D17F17D18F18D20F20D21F21D22F22D23F23D25F25D26F26D27F27D28F28=BCDEFGHIJK4QUARTER DAYS/QTRRATESDAILY RATE     51/1/20013/31/2001909.0%0.00024658 Calculate interest to: 3/31/2009 64/1/20016/30/2001918.0%0.00021918 PAYMENTDATES INTEREST BASE INTEREST77/1/20019/30/2001927.0%0.00019178     810/1/200112/31/2001927.0%0.00019178 112/2/2001 $            2,424  9      21/11/2002               2,486  101/1/20023/31/2002906.0%0.00016438 32/17/2002             21,011  114/1/20026/30/2002916.0%0.00016438 43/19/2002               3,827  127/1/20029/30/2002926.0%0.00016438 54/22/2002             54,971  1310/1/200212/31/2002926.0%0.00016438 65/25/2002               1,255  14      76/24/2002               4,883  151/1/20033/31/2003905.0%0.00013699     164/1/20036/30/2003915.0%0.00013699     177/1/20039/30/2003925.0%0.00013699     1810/1/200312/31/2003924.0%0.00010959     19          201/1/20043/31/2004914.0%0.00010929     214/1/20046/30/2004915.0%0.00013661     227/1/20049/30/2004924.0%0.00010929     2310/1/200412/31/2004925.0%0.00013661     24          251/1/20053/31/2005905.0%0.00013699     264/1/20056/30/2005916.0%0.00016438     277/1/20059/30/2005926.0%0.00016438     2810/1/200512/31/2005927.0%0.00019178     Sheet1 [HtmlMaker 2.42] To see the formula in the cells just click on the cells hyperlink or click the Name boxPLEASE DO NOT QUOTE THIS TABLE IMAGE ON SAME PAGE! OTHEWISE, ERROR OF JavaScript OCCUR.