Numbers not SUMMING

Hey all

I am trying to SUM the values in a column, but I am not getting a running total.

In the column I wish to get my values from, each cell has been populated with a number through a series of IF statements to produce a certain value depending on another cells results. I am looking to SUM those values that the IF statements generate at the bottom of my table, but I'm only getting a 0 in the cell I am trying to put the SUM formula in.

I have made the bottom row a footer row (or at least I think I have) and I have tried to change the cells that I want to SUM to number in Date Format, but the cells just return to automatic.

Hopefully the following Screenshot makes it bit clearer as to what I am saying.

This is the formula that populates the cell with various values, based upon the Pop-Up menu choices in the previous column.

And lastly this is the SUM formula I have attempted to use to SUM the column values.