Avis - Car slightly different to paperwork

Ok so still the same model but I'm noticing more and more that the engine sizes aren't corresponding to the paperwork.
just had a rental where the paperwork says merc c220 cdi, but actually ends up to be a c180 cdi. Other month had a Volvo allegedly D5 ends up a D3.
Lesson is don't get over exited when getting the paperwork to the HP you will actually be getting!

Nobody else experience this then?
I just returned from MUC and again same thing.
Paperwork 2.2 dci qashqai, actual 1.5 dci qashqai.
BTW it's a vert nice car, pleasantly surprised.
Declined an upgrade as all they had were 8 seater vianos!

Honesty, I have never looked at the horsepower or engine I am supposed to be getting. Based on what the Vianos looks like, I would have declined as well.