Need the SQL to balance between OTL and Projects, including Retro Timecards. The current problem is

Need the SQL to balance between OTL and Projects, including Retro Timecards. The current problem is OTL timecard data records does not appear to identify the negative records (appears to only carry positive values).  For example if I originally have 8 hours on my timecard and I want to transfer to a new project, I zero out my original hours.  OTL appears to create a record of 8 hours.  Once saved the zero hours appears.  When I compare the hours in OTL, it appears to have at least two 8 hour entry, including the original, totaling 16 hours.. If the