Label bold & input normal vs. Label normal & input bold

This is a wireframe of an example of a future company styleguide. The styleguide says: option B (label normal, input bold), focus on the content in the textboxes. I have never seen anything like this. What is your opinion? What advantages could option B have?

This form is part of a software for large numbers (dozen of text-inputs) in the accountancy area.

The style decision comes from one of Europe's best UX agencies. I want to understand their goal.

This is a B2B environment using desktop software.