I need an auditor

I was updating some of the numbers in my balance sheet and noticed that when I adjusted one of the line item assets the total gross assets and the net assets (i.e. net worth) didn't change. When using the "sum" function I had managed to miss the last item in one column. In effect I have been understating my net worth for at least part of 2007 (probably since I purchased my last property in June). It's not a large amount (about 0.6% of net assets), but it's irritating that I have been recording and reporting inaccurate numbers for at least a few months.