MULTIPLEX followed a slightly different philosophy with the 35/40 MHz-gadgets in contrast to the competitors. They preferred a higher sensitivity but on the other hand didn't subdue the twitching of the servos. As a result when you switch on the receiver without a tansmitter signal the servos go a bit in the one or other direction. This, however, is corrected when the tranmitter signal is put on.
Sometimes modellers are irritated concerning the neutral positon of the servos. And her again this is due to MPX-philosphy: Untill the production of the mc4000 all transmitters were set to neutrual position of 1.6 ms whereas the competitors preferred 1.5 ms, which is standrad today even with MULTIPLEX!
So long and merry Xmas