HPA 495 with

I'm using the HPA495 for calibration etc. I have a 4-cell board, which is straightforward to connect up.

I also have a 3-cell board. The cell connections are obvious, but where does the Pack+ connection go? P+ on the HPA, it's about 3.7V higher than my highest cell, does that matter or do I just join it direct to 3P instead?

Note, with the 4-cell, I always measure a slightly different  (few 10's of mV) voltage between 4P and P+ so I assume it makes a difference where I put it.