apply an equation over a excel file using python -- 2

The objective of the code is to fill GREEN cells in the spreadsheet named io3, following a rule that will be explained below.
1. For every cell in column B that has a value, for example, P-20, P-25, and so on
1.1 For every value in title line, for example, MSG-RO, PLAEN-NA, and so on
find in the spreadsheet named "inv", the match point. I mean:
if I am in the line of P50, for example, so code will find P-50 to MSG-RO in inv.

Take a look and find yourself.
it is in column "ao", isn't it?


once code has located this column, it will need to do the followin calculation:
(first value in line of P50) - (A x B x C - D x E x F)/1000
where
A = value in column AO, line 5
B = value in column AO, line 9
C = value relative to P50 in the pack in blue, column AO
D = value in column AO, line 6
E = value in column AO, line 10
F = value relative to P50 in the pack in yellow, column AO

note: (first value in line of P50) is the number in column C.


doing all this code should find the number in cell D9, which is related to P50 and MSG-RO.
Next point in this line follows the same rule: find out the column in inv related to the branch MSG-RO to PLAEN-NA
(second value in line of P50) - (A x B x C - D x E x F)/1000
now
A = value in column ---, line 5
B = value in column ---, line 9
C = value relative to P50 in the pack in blue, column ---
D = value in column ---, line 6
E = value in column ---, line 10
F = value relative to P50 in the pack in yellow, column ---


note the source values in "inv" contains equations, which must be kept right there.
note that IO(3) contains drawings, that must be kept right there.