Here's a question for an assignment for my computer info systems class.

I have a table posted below in cells A4:E13

Credit National National National National
Rating Area Area Area Area
Score 111 112 113 114
300 3.00% 3.00% 3.00% 3.00%
325 3.25% 3.25% 3.25% 3.25%
350 3.50% 3.50% 3.50% 3.50%
475 4.25% 4.50% 4.75% 5.00%
550 4.50% 4.75% 5.00% 5.75%
650 5.50% 5.25% 6.00% 6.50%
750 6.50% 5.75% 7.00% 7.25%

Shipping Rate Per Pound Shipped is $4.00 (4 is placed in cell E16)

B21:G25 for this partial example of the table...
Credit Shipping Total Total
Customer Rating Destination Weight to Discount Shipping
Number Score Area Ship (lbs.) Amount Cost Invoiced
100234 487 111 2,987 ? ?
100543 300 114 15,487 ? ?
etc. etc. etc...

I need to calculate the Discount Amount based upon a customer's credit
rating score and from there calculate the total shipping cost for that
customer. I must do this TWO ways using the VLOOKUP function. I must do
these both where I only have to type the formula once and can just copy it
down for each row of the table that calculates shipping costs. I must
provide two versions of the VLOOKUP formulas: 1) VLOOKUP using a nested IF
to definte the col_ind_num, and 2) VLOOKUP using a calculation to define the
col_ind_num.

I cannot figure out how to properly use the function -without- using nested
IF functions. Any suggestions?

P.S.
The current formula I have is
=VLOOKUP(C24,$A$5:$E$13,IF(D24=$B$6,2,IF(D24=$C$6, 3,IF(D24=$D$6,4,IF(D24=$E$6,5)))),TRUE)*E24*$E$16