MB 320E 2005 washer wierdness


Driver side washer started to get weaker and weaker til finally it was a dribble to nothing. Passenger side, no problem, still strong.
Had a cursory look, but I am not mechanically inclined, nothing evident, ie no apparent kinks or leaks.
Asked the mechanic (not a dealer, but a foreign car "expert") to look at and he advised that the pump is fine (ie passenger side) but the nozzle is broken. The nozzle is a closed system and appears to house some kind of powered device (there is a plug with connections). OK.
So we ordered a new nozzle (not cheap! over $100) and it was installed. Driver side is a fire hose! Great, but, and here is where my question arrises, the passenger side is now weak, to a dribble.
The pump feeds both nozzles but the mechanic is saying that the new nozzle is an upgrade and it is stealing washer fluid from the passenger side. I need to buy a new nozzle for the passenger side in order to equalize the pressure and fluid distribution.
Does this sound right? Anyone else experienced similar? Ideas?