The whole Retina display thing is a) subjective, and b) down to the distance you hold the device. The '300 PPI = Retina resolution' was for a device held 12 inc

The whole Retina display thing is a) subjective, and b) down to the distance you hold the device. The '300 PPI = Retina resolution' was for a device held 12 inches away (or something like that). The iPad is held further away, so the resolution required for 'Retina resolution' is lower.