I have a MacBook Pro with an NVIDIA GeForce GT 750M. I only am presented with the renderer option of Mercury Playback Engine Software Only when creating a project. The MacBookPro was the top of the line when I bought it in Jan. 2015. Is this correct? The words "Mercury Playback Engine Software Only" are greyed out and the drop down arrow does not bring up any other options like I see when watching others using PP in videos. I am using PP CS6. Is this the way it should be, or is this an error/problem?