Hi donovanpl123
Yes. I agree that there is some confusion in the illustration of how the voltage sensing is done, in the AN564 app note. In the schematic in Figure 16, L2 line must be tied to AGND. It will be corrected in the next revision of the document. So, the voltage channel sensing is done between L1 and L2, with L2 grounded.
For sensing the sum of two currents, I believe using a single CT by wiring currents in opposite directions, is the easiest method. If you are interested in using ICs like ADE7953 (which has an additional current channel), then two separate CTs can be used and the sensing is done independently.
The App note AN639 has questions that deal with such configurations and I feel it would be useful to you (page 13 and page 5).
It is your choice if you wish to sense the voltage between L1 and L2 or between L1 and N. One of the terminals must be grounded so that a single ended signal is provided to the chip and this also ensures that a stable reference point is achieved. Be mindful of the direction of current flowing through the CT- install the CT such that the direction matches with how the voltage channel sensing is done.
Let me know if you have any more questions!
Regards
hmani