Most common tire size on 97 528i

My 97 528 in riding on tires sized 225/55/R16 tires. The inside of my
wheels are stamped 7Kx16. The manual states that the tire specification for
this is exactly what is on the wheels; 225/55/R16.

When I research tires I find that there seem to many more 225/60/16 tires
available than 225/55/16. A local BMW mechanic is adamant that 225/60/16
are what is supposed to be on this car.

I suppose the wheels could have been swapped, however they are BMW wheels
and seem to be about the correct age ( base on what I think the wear should
be ). This wheel is aluminum and has 20 ribs in it.

What do you think? Was this wheel common on a 97 528? Could my car
originally have come with tires sized 225/60?