The imperfect refers to present time or (sometimes) to a continued or habitual past act or state. The imperfect may be conative.
εἰ ταῦτα ἐποίεις, καλῶς ἂν ἐποίεις
The implied opposite is a present (ἀλλ' ου' ποιεῖς
The imperfect of past time emphasizes the continuance of the action.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].