Paper Trading to Live…ToS Order Fills

Recently I have been paper trading SPX Iron Condors on the ThinkorSwim desktop platform.

For reference, this week I have been trading $20-wide wings on both sides, and targeting trades that show as 52-53% P(profit) and offer total premium of close to $10. (Earlier this week these showed as positive EV for the 9/20 expiry, now have all turned negative, so none active rn.)

I have been using limit orders and routinely get hit immediately on the price the system shows (which is usually around the midpoint price I see in my analytics).

But then I'll set a limit order to buy back at, say $9.00. And sometimes I'll see this get filled at a price WAY better than the limit.
Is that real? In my experience wouldn't the MM just pocket the gap?
Are you all getting filled at prices BETTER than your limits?