Boost converter efficiency, TPS61021A
Pin = 1.2V &times; 570mA = 684 mW

Pout = 3.3V &times; 105 mA = 346.5 mW

Efficiency = Pout/Pin = 346.5/684 = 50.7%

How on Earth did you come up with 18.42%?

Similarly, I get 64% and 70% for your other two loads. These numbers actually sound pretty good to me at these voltages. Did Webench give you any efficiency estimates for this specific configuration?