I'm sure I have misunderstood the concept of dual mono, so I would love if someone can explain a thing or two for me:

I have a Shadow Hills Vandergrah in my 500-rack - which is a stereo compressor (not dual mono).

Since it is not dual mono I have just assumed that weird things will happen when sending two separate mono-tracks to it.

But when I sent a stereo-stem through a pair of mono-preamps (slot 5 and 6), and then into each side of the compressor (slot 7 and 8) - it sounded all fine?

Is it supposed to sound fine? I couldn't hear anything weird. Would it have sounded different if it was a dual mono stereo compressor? Have I just misunderstood the concept of dual mono?