Why Aquila horsepower figures differ

Why do sources give Aquila either about 220,000 or 150,000 shaft horsepower?

One proposed explanation is nominal machinery output versus estimated installed performance, but neither figure was confirmed by trials.

Aquila never completed trials, so neither horsepower figure can be treated as a measured result from the finished carrier. One proposed explanation separates the machinery's nominal output from its expected performance after installation. The conversion used modified propellers and involved compromises that could have reduced the installed rating. The suggested relationship between 220,000 and 150,000 horsepower remains conjectural because the ship never tested the system at sea.