I'm new to diving, but that "less weight" idea looks wrong to me. On a couple of early dives, I used the minimum weight I needed get down, thinking it was somehow safer. As my tank emptied, I had to fight to stay down (using more air), and on my safe ascent I corked to the surface from about twenty feet with an empty BC because of tank buoyancy.

Doing things wrong to "save air" is foolish. Dive more and get better at it!