Many divers would have difficulty especially at the beginning of the dive. They would be at least 4 pounds over - weight at the start ( 2 lbs. due to tank -AL63, 2 lbs. - AL-BP ). Also, smaller divers with smaller lungs are not able to go up with a deep breath until they add air to their B.C.I'm simply having trouble visualizing a body type in AL63 and aluminum BP that wouldn't go up if they took a deep breath... Maybe a 230 pound linebacker with 1% body fat?
The point is why add the extra weight when it is not needed!