Disklavier

I have an MPX 70 Disklavier with the Silent facility.  When I play it in Silent mode and listen through headphones, I find that in pieces with lots of notes, or fistfuls of notes or perhaps combined with use of the sustaining pedal, the sound of the notes especially in the treble is noticeably delayed compared with the time they are struck. You can see examples of the type of music in which this is especially apparent on some of my YouTube videos (search for honkytonkpiano).  Is there a way round this, or is it simply a problem with limited computing power in an old Disklavier?

Advice would be appreciated.

Regards,

Mike Thomson