Exactly. The problem with the open-endedness of "let me know how I can help" is not always with respect to time. It is more often with respect to what will actu

Exactly. The problem with the open-endedness of "let me know how I can help" is not always with respect to time. It is more often with respect to what will actually happen next. The statement "let's talk at XX:YY on the ZZth" only works if time is the primary indefinite aspect of the next step. In the case of these prospecting emails, the primary indefinite aspect of the next step is "what value will you provide".