The "Filtlu" is really Filtlv = Filter level - the small font on the screen does not make a good distinction between the u and the v. This is the amount (level or lv) of midrange EQ adjustment. Filtfq is Filter frequency and is the midpoint of the midrange band EQ adjustment. In the manual this gets called Tone Quality Control. CC27 is Filtfq and CC26 is Filtlv. Please see page 41 of the manual for slightly more info.