These statements are not correct. Remember the addage, in series voltage adds while amperage stays the same. In parallel, amperage adds while voltage stays the same. So, two 8.6A panels wired in series is NOT 4.3A + 4.3A. It just stays at 8.6A.Your top first diagram shows 8.6 amps going through the 2 in // (edit: the original panel with the spare in //)
This should be 4.3 amps though each // pv When you have this the V across the 2 in // will rise and the V across the series will rise the same. The increase will be somewhere between Voc & Vamp depending on the PV's properties. Even though you still have the same current going through the series, it is at the slightly higher voltage. Thus wattage has increased.
In terms of voltage the Vmp and the Voc would both be exactly double what a single panel would be. There will be NO averaging of the Voc & Vmp.