I found the solution. I looked in the MIDI implementation manual/pdf, on page 17 the sysex codes for the MFX1/2 Tone part effects start with 18 00 02 00.

I got rid of the 18 00 02 00 and the 18 00 08 00, as a result MFX1 and MFX2 are not changed once the MIDI file starts playing.

So I can change the TONES in Up1 and Up2, the MIDI file has no influence on MFX1 and MFX2.

The 18 00 02 00 was clear to me that deals with MFX1, but the 18 00 08 00 I found by trial and error, and that seems to deal with MFX2, I just don't know whats the meaning of " MFX control 2 sens" is. See if you can make any sense what's the reasons that it works.