how to write a nested if formula with special conditions

I thought that a nested if is what I needed, but now I don't know what I need I have explained in greater detail within my sample that's attached.

I don't know how to write a function for what I need.
Right now I have a function that says '= if $b7=0,0,if($d7>$d5,-1,1)), but I've found a problem.
If there's more than one zero it throws off what I'm doing.
I need a function that will ignore any zeros within column D and use the second to last number.

For example:

The formula in E12 should read '=if($B12=0,0,if($D12>$D8,-1,1))
The formula in E13 should read '=if($b13=0,0,if($D13>$D9,-1,1))
The formula in E20 should read '=if($b20=0,0 ,if($d20>$d12,-1,1))

I just don't know how to write this so that it will go back to the second to last number other than zero.

what do you mean the second to last number? what result should be in column e
edit oh i see hmmmm
ok perhaps like this with a helper column and new formulas where indicated