AIUI Direct Mount Guiding (DMG) is a feature of TheSkyX which takes an offset value and applies it rapidly rather than the usual pulse guide command that makes a move for a time at a rate that’s no more than the sidereal rate. The DMG offset is applied much faster than the equivalent pulse guide.
AIUI the only way to access it is through the TSX ASCOM interface by issuing PulseGuide commands. The driver converts the time and rate information to the offset that Direct Mount Guiding uses.
One feature of DMG is that the correction is made in a fraction of the time that a pulse guide would take and this can confuse some applications.
A lot of speculation here but maybe it will help.