The 180 has more power and torque I think, so that ad does sound strange.

 

Don't let the model number at the back of the car fool you. Mercedes doesn't always tie the model and engine size together. In the old days, that was usually the case. So a B200 may have a 2.0 engine, maybe not. In your case, the B180 (model) was available with at least a couple of engines.

You may not speak German (mine is rusty, lol) but the .de (German) websites are gold. Check it out...shows engines and models:

Mercedes-Benz T 245 ? Wikipedia

 

The B160 was the facelift version of the B150, and had a 1.5 litre engine. That engine has enough power to keep the train running, but do not expect to do ANY serious accelerations.
I.m.h.o. the B150/B160 is just underpowered. Period.

The B170 (pre-facelift) and B180 (facelift) are the minimum engines you need for a smooth drive.