Need to be able to calculate the total of column data in order to be used in reporting metrics

Well, the sum() function can do that for you.

Can you explain how though because I tried that and it didn't work. It's not as simple as entering =sum(recordtype!dcloans.fields.principlebalance) somewhere? Or even if it is, where would you use that formula?

Well. You need to use the actual values, not just a reference to some field in a record.

=sum(local!YOUR_DATA[recordtype!dcloans.fields.principlebalance])

Ok, I know this is a pain, but I am still trying to learn this stuff and I am really under the gun here so I could really use some hand holding here. To start, where would you create that local variable to capture the principal balance data? And would it be local!principalBalance?

Next question would be, where would you put that sum formula to display the result?

The variable you are using to hold the grid data use that same variable in the sum function and for referencing the field to be used inside sum we use recordtype!recordName.fields.columnName
Once you type recordtype! you will get the necessary fields.
(The above solution is when you are using records to fetch data, in case using cdt use index function inside sum instead index(arraywithdata,"columnName",{})

The variable you are using to hold the grid data use that same variable in the sum function and for referencing the field to be used inside sum we use recordtype!recordName.fields.columnName
Once you type recordtype! you will get the necessary fields.
(The above solution is when you are using records to fetch data, in case using cdt use index function inside sum instead index(arraywithdata,"columnName",{})

I need to be able to display all this information on a reports interface, so can't I create some sort of GetPrincipleBalance query that grabs all that data from the various records and then utilize that result in a sum function somehow?