In a BBL If a total of 1800 cc are out with the lipo, on average, how many cc of fat do you get for injection?

The nurse told me they were only able to take 1800 cc and only injected 450cc per cheek. Is this the average amount that is used. 900cc of pure fat? My surgeon told me I didn't have a lot of fat to harvest and I said it's ok because I didn't expect to end up with a huge butt and I didn't want a huge butt. I'm worried he took that to the extreme and was too conservative with the injections. I usually see this small amount used with very thin girls.