Hello George,
Seems like the "bowl-effect" is not completely removed during optimization.
Even with unused 4 and 5 points the positions or GCPs are OK (however, it would be better to use more points n the center and on the bottom).
Could you please check the markers with large errors - seems like these are: 10, 11, 8, 9.
After that we recommend to optimize the alignment with marker accuracy set to zero.