Business & farm

Well I entered a big long post on all the issues I was having keying in the data. However I don't see my post here so maybe that's a good thing. I deleted everything and started over and now I have all my information and it look similar to last years except the prior depreciations are all off. Current depreciation is always 0 which is probably right the lifetime said 7 years and it's been 7 years. But the prior depreciation column does not match last years sheet. The difference between my original cost and prior depreciation is now about $600 where is last yesr it was bout a $172.  Can I somehow update the prior depreciation column.