Hrqls: I think you are right, but that there is a difference only if you roll 2-1 or 1-1 with your next roll. If you roll 2-1, 6/4/off will likely win a roll in comparison to 6/1 5/2. If you roll 1-1, 6/4/off will likely lose a roll. Since 2-1 happens twice as often as 1-1 and you are way ahead (so after 1-1 you are very likely to win anyway), 6/4/off seems clearly better.
It is probable that if your opponent was ahead and you desperately needed doubles, 6/1 5/2 would be the correct move. I doubt there is much equity at stake in any case.