Transpose with transpose latch on. Save. This works in the same fashion as gate or velocity shift, which is why there is no note shift, but is not a solution to the above question.
Just reread your question. There is no easy way to transpose only 16 steps of a 32 step sequence. Even if there was a note shift type function that work like the gate and velocity shift work (press and hold shift then turn the related knob), it would still transpose the entire sequence, not just the 16 steps you are focused on.