>If row buffering is enabled, I need to run TABLEUPDATE() to commit the changes after running REPLACE command.
>
>Do I also need to run TABLEUPDATE() after running REPLACE ... FOR command?

With row buffering enabled, an implicit tableupdate occurs when you move rec pointer. With replace for... you would move rec pointer so all rows are updated implicitly. In short answer is you don't need.
Cetin