Wholesale prices are produced by running the SPD model. SPD only models the transmission grid, i.e. points in distribution networks that are remote from the grid are not included in the model. There are about 500-600 shadow prices that drop out of SPD but only a subset of these get published by the pricing manager as wholesale spot prices. The precise number changes from time-to-time as assets are commissioned or decommisioned. I think there are currently 243 points at which prices are currently published. See EMI or WITS.
But there isn't necessarily injection and/or offtake at all of the points at which a price is determined or published. For instance, I think there is injection at less than 100 of the 243 points at which a price is published.
As for the Points of Connection (POCs), GXPs, GIPs, nodes, pnodes or whatever you want to call them, and they get called many different things all the time by the Code and the various systems that make the wholesale market work, I assume you know how these things are labelled? The first three characters generally denote a geographical location, i.e. BEN for Benmore, OTA for Otahuhu, etc. The next three characters (or first three digits) denote the kV of the particular part of the transmisison network, i.e. 220 for 220 kV, 110 for 110kV, 066 for 66 kV etc. The last digit denotes the bus or switch (I'm an economist, not an engineer). So I'm guessing BEN2201 and BEN2202 are bits of kit that sit right next to each other in the same switch yard at Benmore. The prices at BEN2201 and BEN2202 would be almost identical, even if not both of them are published.
It therefore wouldn't surprise me at all to find published prices but zero offtake at BEN2202. Try checking BEN2201 - maybe the flow is recorded there?
You may also find the SPD network diagrams helpful.