Understandably being the pro.. you want to stay on schedule, and not draw negative attention to yourself by appearing 'obstructive' to those in the studio trying to get the tracks layed down...
Why was the original bass track deemed unusable by the engineer? Was there no further comment from him on your first effort? Did the person producing have no input? Maybe there was a plan to have two differant bass-line styles as to have a creative option at a later time? Maybe the Engineer is just not a talker...

maybe I ask too many damn questions (Roger that!)