put $2.5k into a mid-cap through a dex and walked away $180 short, what went wrong?

swapped $2.5k worth of ETH into a mid-cap token recently. the preview showed 3% slippage, I set my tolerance to 4% and went ahead. came out $183 below the quoted amount. the pool showed roughly $800k in 24h volume so I assumed it was fine. I

s this expected at this size or did I mess something up?

EDIT: looked into fixed-rate options after this thread, SimpleSwap has one. you lock in the rate before sending, so pool movements between quote and execution don't affect you. would have saved me the headache here.