I'd never heard or read of the phrase "ice cream chords" until your mention of it. It does sound to me like it was coined by someone trying to sound deprecatingly cool. Regardless, choosing ice cream as the reference is suggestive of US origin. Had it originated from the UK or Commonwealth in the past, 'bread 'n butter' would be the more likely euphemism. Not deprecating, just to the point honest.

I like both progressions.

And undeniably pleasing to the ear they are.