Why does my Apps Script reference the wrong row? - google-apps-script

Question

The Goal
I am trying to create a spreadsheet using some custom functions. The purpose for the sheet is to keep score in a quizzing competition. The top row has the question number, the second row the score, and the third number the number of fouls for that question.
The Problem
After noticing some problems with the score calculation, I was able to narrow the problem down to the part of the code where I add up the fouls that occurred prior to the current question. It seems that no matter what I do, the code sums over the question row, not the foul row.
Attempted Solutions
The extremely strange thing is that no matter what I change the reference cells to, it always produces the same result (i.e. it still references the question row same as it always has).
Example
I'm not sure if that makes any sense, but I've made an example sheet here so you can see what I'm talking about and try to figure out what is going on. Keep in mind that I'm well aware that I could accomplish what I'm trying to do in the example sheet with a simple built-in formula, but since there's no way to use worksheet formulas on the Apps Script side, I have to create my own version of it. I've made the example editable for anyone with the link, so you should have full access to it; but if you have problems, just let me know, and I'll see what I can do to fix it.

Answer 1

In your For loop, you are summing the indexes rather than the values:
Try:
for (var PrevValue in PrevValues[0]) {
Sum = Sum + Number(PrevValues[0][PrevValue]);
}
EDIT:
You'll also need to account for the case where you pass in a single cell rather than a range (=mySum($B4:B4)), because in that case the value is passed directly instead of an array.
if(PrevValues instanceof Array){
for (var PrevValue in PrevValues[0]) {
Sum = Sum + Number(PrevValues[0][PrevValue]);
}
}else
Sum = PrevValues;