Custom column summing multiple columns - some rows not summing?

The first thing to note is that a null value in a formula is not a zero. And a null value is not equal to a blank value.

One solution is to replace null by 0 in each column using Replace Values.

Another solution is to create the costum column with the function List.Sum this way:

Short-Term Savings = List.Sum{(Checking Account(s), Savings Accounts(s), Cash)}

UPDATE!  I figured it out.  I just needed to replace the null values with 0.00 and now it works.  Leaving this here in case someone else has the same question.