How to set zigzag setting not to show length that less than 20 pips?

 

dd

I want zigzag draw line on at least 20 pips length. Currently my setting is 20 Dept, 20 Deviation, 3 backstep. But it show 14.7 pips, 12.8 pips length as picture above. Any idea how to make zigzag show only 20pips and above length? Or any custom indicator can do that?