While on Nikon you need motorized wheels to come through all these 1/3 stops and you're busy for a while if you want to close aperture down (that will teach you next time not to mess around with manual settings, ha, those wheel are only for the look and feel),.
That's why I usually set the camera for 1/2 step exposures, it becomes much faster to dial in what you want. However, Sony doesn't care about that when you turn the Exposure Compensation Dial on the right hand corner. Since that dial is in 1/3 steps only, camera switches back to 1/3 step mode. Probably same thing if you happen to have a lens with 1/3 aperture ring.
If you happen to have a Canon 85/1.2 mounted on your A7, you can set the aperture at f/1.2 only if you have selected 1/2 step increments. When you apply exposure compensation, it's f/1.3.