Sounds like you didn't get the correct advice from whoever trained you and it would appear that nobody checked your log book before verifying it to be correct. That said, why not just cross out the hours in the Dual Column with a pen and write them in the In Command Column, its only a log book!
Or, you could stick two pages together and start again on the next page; I have a log book here from 1937 with the first two pages glued together.