More like the GOM and SOC-based estimates converge as the end of a trip approaches. Leave it to Nissan to give you a range estimator that only becomes accurate when you no longer need it. HOWEVER, assuming this is an SV or SL (I've forgotten), there is a much more accurate range estimator available. Press the little blue-ish Energy button on the steering wheel, and the Nav display will show you a regional map with two concentric white circles overlaid on it. The large circle is the GOM range estimate, but the smaller circle is a more pessimistic, generally surprisingly accurate, second range estimate. Use that one....after some time at 45mph with AC off the GOM and % started to match up. When I arrived I had 21% and 18mi left.
Looks like at constant speed the GOM gets pretty correct, but yes, I did have the % displayed and I was monitoring it closely.