lightning

Hoping to reduce the number of my UTXOs from four to one, I ran [this command][1]:
```
lightning-cli -k withdraw destination=destinations_address feerate=4000 satoshi=all
```
 The command did reduce the number of UTXOs from four to two. Why didn't it produce 
just one UTXO?
What has your experience been of consolidating UTXO on Core Lightning? 

[1]: https://docs.corelightning.org/reference/lightning-withdraw