Add all prior values of last cell is >0

[NewbSauce]

Please help as I have spent several hours trying to figure these out. Thanks so much in advance. Will offer compensation if you can help, hope this is allowed.
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Issue 1

I have a row of 12 numbers indicating forecasted hours (row 18)

I have a row of actual hours (row 19)

I want to add all of roe 18 until there is a value in row 19 then stop.

Currently doing sumif(c1919,,”>0”,c1819)

The challenge is if c19 is zero and d-f19 has a value then it naturally only adds if the d-f.

What formula can I write to tell it if F greater then 0 then add c-f.

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Issue 2

I’m using the average and nesting it with a product.

I want to average a row of 12 numbers only by the amount of values greater then zero.

Example:
I have c-d with random values e-h with zero. I want it to find the average of c-d without taking into consideration e-h.

Ultimately adding c-d and dividing by two and not the 4 zeros in e-h.

Is this possible?

 

[6StringJazzer]

This is the answer to issue 1 but it doesn't make sense that you would have actual values in the end with blanks at the beginning.

=SUMIF(C19:O19,"",C18:O18)

Issue 2 is simple if your version of Excel includes AVERAGEIF (2007+)

=AVERAGEIF(C19:O19,">0")