Sennheiser ENG SET ew122-p setup

Hallo guys,
I've recently bought a Sennheiser ENG SET ew122-p but I have problems with Levalier cardioid clip-on microphone M4.
Ricever EK 100 G3 is ok with Af out 0Db.

SK 100 G3 bodypack transmitter is ok with "Sensibility" -18Db

but...

EK 100 G3 Reciever linked with Levalier clip-on microphhone M4 is really noisy, like a omnidirectional microphone...
I've checked the EK 100 G3 set up and "Sensibility" value was -30 Db... I've turned this value to -18 Db like SK 100 G3 but I don't know if is a good o right solution. Have you had experience with Sennheiser Kit?

Thanks!