If the server has all the data, and does the homomorphic math, couldn't it selectively change some of the data inbound to a second job with the same user inputs

If the server has all the data, and does the homomorphic math, couldn't it selectively change some of the data inbound to a second job with the same user inputs, (in the background) and compare outputs, eventually using a a binary search to figure out what data was selected?