How did my boobs not get bigger after under muscle, 450cc, silicone implants?

Breast lift with 450cc silicone implants. Im still measuring same and no increase in size. I had a breast lift with 450cc silicone implants at 33. It has been 6 months and i am in the same bras as i was before surgery. My breast are high, tight, and perky. But not bigger. I do have more upper fullness but i do not feel bigger. I measured at 40 in across my nipples before surgery and still measure the same and wear the same bras. How did my boobs not get bigger after implants? The implants are under the muscle.