Do implants "drop" after an implant exchange?

I had 10 yr old saline implants swapped out for silicone gel nearly 3 weeks ago. I had no record of the cc's of the old implants, so the surgeon had to estimate by measuring in surgery. The goal was to keep the same size, but I feel like my breasts look so much smaller now in clothes. Will decreased swelling make them even smaller over time, or will they "drop" fuller again as they did the first time? I did have a pocket revision to make them sit a little closer together on the chest.