My guess is that your vehicle was actually totaled because of the structural damage but neither the body shop or the insurance company will tell you that. Where you will really see the hit is if you take it to trade it in on another car - that’s where your diminished value will show up on...
I think it may be closer to 2/3. I believe the total capacity is around 6 quarts so you drain 4 1/2 quarts that means there’s a quart and a half in the torque converter. So probably closer to 2/3.