SUMPRODUCT that ignores strikethrough

So, I know it has to be a custom function. I have tried building one in VBA and have not real luck. Any ideas how to build a function that works just like SUMPRODUCT but ignores cells that are strike through.

I guess we could make it a cell fill color function instead, the important issue is being able to see the data but not have it calculated in the SUMPRODUCT function.

Am I dreaming that this can be done? I am very new to the world of custom functions and have used a few, but this one is kicking my rear.

At this point it is manually selected and changed to strike through when the task is complete. I am contemplating having to add another column with a data validation list set that will allow
for a "complete" to be selected for a row and that would conditionally format the row to strike-through font. In that case, I would just key if off that column. Just trying to add some new
functionality that was presented as a want. If the strike-through dependent custom function is too much of a pain I may just take the easy way out.