Retirement tax questions

Thanks for the response. Box 1 18438.58 and box 4 3687.72 which is would only be 20%. I assumed that was just listing the additional amount I withheld since the penalty is a fixed rate so just wasn’t listed, and when I filled out my withdrawal form it already accounted for withholding 10 percent and then asked what I wanted to additionally withhold, I worked for the FAA so it was a Thrift Savings Account(tsp) not an official 401k but my understanding is they work the same. I’d have to go to the bank to get statements for it but I’m 100 percent positive I only received approximately 13k back which would be about 70%. Side note from that though is if I withheld just 20% wouldn’t they still only need an additional 5% not 10? Or is it taxed in the next bracket and counted as income? I guess the point of asking is if everything was done correctly and the 1099r is wrong and I did withhold 30% should I be even?