I have a financial matrix where I have the current month's principal and the previous month's principal. I want to calculate the month over month change within my matrix. So, for example, loan 1 has a current balance of $10,000 and the balance last month was 11,000. I want a variance column that shows the $1,000 change. The matrix obviously "pivots" on the date column. Any help would be appreciated. Thank you.