I guess I'm doing a poor job of communicating :/ . Once I open up the EL for the track, I see several categories at the top: Trk, HMSF, MBT, Ch, Kind, Data, and a blank. Once I change Kind to Control, I'm assuming you're talking about changing Data to "20"? I see text options for other types of controls, such as modulation and expression. I would expect to additionally see CC20, CC11, etc.
Can I assume the box to the right of Data that is unlabeled is probably 'Amount?'