Well, it's a somewhat different plugin, works totally differently. The caneditrow and candeleterow plugins have their PHP run as the list is being built, prior to being displayed, and have access to all the list data, and it's a simple case of "can the user edit this row".
How would you expect the 'condition' on update_col to be applied? On a per row basis, or on a per-field basis, given that you can provide multiple fields/values? Would you need access to the full row data?
Give me some more details on what you are needing to do ...
Oh, and I'm not wild about adding new features to 3.0.9, do you really really need it on both 3.0 and 3.1?
-- hugh