Yes. This mode is actually more likely at higher speeds, because if the computer does not place the vehicle in it, the MG1 speed approaches its design limit. Remeber this, when you are in the "heretical" (I prefer Electronic-Recirculation or E-Recirc) mode, the output of MG2 is used to reverse turn MG1, the change in torque at the PSD meshed gear surfaces resuts in a lower shaft speed for the ICE -- the best parallel in a conventional transmission is overdrive.
To understand it go here:
http://eahart.com/prius/psd/ and scroll down until you get to Alex's PSD animated simulator at the bottom third of the page. Set the value for the ICE at 3000 RPM (Don't worry about the distortion in the nomograph), then set the value for MG2 to the same value. Note the speed of the vehicle and the fact that the sun gear is moving at very close to the same speed as the ring gear. Now, reset the value for the ICE down to 1200 RPM or so. What happened to the speed? Nothing. The ICE is now turning a little slower, and its producing less power and burning less fuel. Is this VooDoo or did Newton have it all wrong? No. The answer is that the assumption for a constant speed means that the actual power demand on the ICE is adequate at the slower RPM to sustain the desired speed even if you consider the feed back inefficiency of the MG2 to MG1 loop. Both are steady states, but the second one uses less fuel and makes less power. In other words, the first situation was like driving 50 in third gear in a four speed, and then we "shifted" into top gear. Now, if we apply that in a real-world situation, the difference will not be as extreme becasue any power reduction or increase will impact the vehicle speed to some extent, but the principle is the same.
My earlier posts on this subject dealt with techniques to lower the speed at which the mode is entered or in which it can be sustained (sort of like shifting a manual transmission when you have barely enough revs to support the higher gear). Actually, while a lot or research has been published here and elsewhere on Pulse and Glide, the steady state E-Recirc mode has not been very well researched. Further, I suspect that is much more important in the TCH and HiHy than it was in the Prius because of their additional weight and power. I would like to see some practical research, graphs and techniques, based on experience for use of this mode.