POLY to MONO doesn't work MPC2000XL

Hey guys,

I just purchased my MPC couple of months ago.
I started out with reading the user manual and now i'm starting with the Beat making MPC2000xl E-Book
i have purchased on this site. I have read it al the way thru until the topic (Editing Sequences Part 2) Very helpful b.t.w.

Well, this is my problem.
After i assigned each sound to a pad in DRUM 1 of the PROGRAM menu, i go to PARAMS to change the
VOICE OVERLAP from POLY to MONO.
As far as i understood this should terminate the voice overlap and the sample wil get cut by hitting another sound/PAD, that contains a sound.

Wel here is where the problem starts.
The sound doesn't overlap when i hit the same PAD. But it does overlap when i hit diverent sounds/PAD's.

Example:
When i hit PAD A1 over and over, it cuts the overlap.
When i hit PAD A1 and cut it with A2 (witch contains a sample), it doesn't cut the overlap.

This is the first time i used this option and according to the info and video's i have seen and read, this should not hapen. I'm confused
I did update my OS to the latest 1.20 version... But i don't think this could be the problem.

PLEASE HELP

PS.
I hope my spelling is ok, English is not my Mother tounge. THNX.

Ok thank you verry much.
I understood it wrong than.
I wil check out the mute assign wright away.