Surprising discovery: 5-speed vs 6-speed automatic

The Allison 1000 GM uses started with 5-spds, and added a 6th while retaining the same ratios 1-5.

Dodge/Ram has played a few tricks with its 4turned5turned6 speeds as well.

What did Toyota do with the axle ratio? If it is the same, then lower engine speed on the highway unloaded is all you will see, maybe a little less fuel used. If the axle ratio was shortened (numerically higher), then you may get an improvement in gears 1-5 while retaining a 6th gear equivalent to old 5th.