Conditional formatting with multiple criteria

I am trying to do a conditional formatting based on the result in one cell but it needs to add up multiple cells first to determine which conditional format it needs to use. I am not sure whether I need to do a formula conditional format or whether to use cell is greater than with =sum() in it. I have tried both but neither seem to be working correctly.
I have attached an example of the spreadsheet and the conditions I am trying. I am using 2010 version.

Basically, the closing amount for Monday in prod 1 (cell c4), needs to display in red if sum of the cumm value for Tuesday (L4), Wed (N4), Thur (P4) & Fri (R4) is greater than that value or display in amber if the sum of the cumm value for Tuesday (L4), Wed (N4), Thur (P4).

I need to complete the same for the whole column for Monday (col C) for each appropriate product. Then the same for column B but this will sum different cells but the principal will be the same.

Any help on this would be great as I am stuck!
Thanks.