I'm using row buffering and therefor in 'add' mode the data is only saved to table at end.

Do yourselg a big favor and swith to table buffering. The reason is that when you use row buffering, VFP will automatically attempt to update the current record whenever the record pointer moves. There are a lot of commands that move the record pointer behind the scenes, so with row buffering you will spend a lot of time trying to fight what VFP is trying to do.