Printer shape settings

I have problems with the Y axis. I do not get the right size of printouts in the Y dimension.
I now looked at the “Printe Shape” settings, that I have not changed (at least not intentionally).
I have these settings by default:

X Min: 0 | X Max: 200 | Bed Left: -38.7
Y Min: 20| Y Max: 200 | Bed Front: -5
Print Area Width: 240
Print Area Depth: 215
Print Area Height: 190

Are these really correct?

X: 200 - 0 - (-38.7) = 238.7 (close to 240)
Y: 200 - 20 - (-5) = 185 (quite far from 215)

I do not really understand the “Bed” thing and what the negative numbers there mean.