I've noticed that barons and bonanza's tend to start with full throttle and mixture. Why do they this as opposed to other aircraft that keep throttle at 1/4 inch and put full mixture forward for a few seconds?
According to this website showing the Beechcraft Baron Pilot's Operating Handbook (POH-Beech Baron 58), the engine start procedure is different than you state in your question.
Before start, the mixture is full rich, propeller control is high RPM, throttle is full open, fuel boost pump is on high until the fuel flow peaks then off, then you close the throttle, and then you open the throttle approximately 1/2 inch.
If the engine is hot and temperature is at or above 32 degrees C, then the procedure is a bit different, but not as you describe in your question.
(see the procedure in the images below)
(highlighting is mine)