OK, it would seem fair for me to relate my own experiences on two big-bodied mule deer.
The first buck, the bigger-bodied of the two, was shot by my hunting companion at 311 yards using the Hornady 143 ELD-X factory load. The buck was standing quartering away somewhat, and at the shot did the typical heart-lung shot hop, then trotted 25-30 yards, going slower and slowed until it fell over dead. The bullet entered the middle of the left ribs and was found under the hide of the far shoulder, retaining 74.7% of its weight.
Mine was shot at 101 yards as it stood broadside in some Gambel oak brush. Because of intervening brush, the practical placement was through the shoulders, and at the shot the buck dropped and never moved. The bullet was recovered from under the hide on the far side, after having broken both shoulders, retaining 60.2% of its weight. That buck's boned-out meat weighed exactly 100 pounds, indicating a live weight of at least 250. The other buck was noticeably bigger.
Two comments on your incidents: I have seen all sorts of reactions from frontal shots, and even frontal shots that did the amount of damage you describe. I don't think the buck going far despite LOTS of internal damage such as you decribed can be blamed on the bullet.
The second instance involved a first shot that only hit one lung. I also don't think the need for the follow-up shot can be blamed on the bullet.
