Am I reading these graphs correctly that he’s getting more capacity when using higher discharge current on some of these batteries? How is that possible?

Energizer Lithium:
3317 mAh at 300 mA
3152 mAh at 100 mA

Rayovac Fusion:
1884 mAh at 300 mA
1844 mAh at 100 mA

Rayovac:
1589 mAh at 300 mA
1465 mAh at 100 mA

Eveready Silver:
1384 mAh at 300 mA
1279 mAh at 100 mA