Why is else if block ignored when I add else block?

Why this happens? I'm doing exercise on FreeCodeCamp (Return the lowest index at which a value (second argument) should be inserted into an array (first argument) once it has been sorted. The returned value should be a number.) I know there are better ways to do this but I'm interested in this problem. This is my code:

function getIndexToIns(arr, num) {
let pos = 0;
arr.sort((a, b) => a - b);
console.log(arr);

for(let arrs in arr) {

  if (num == arr[+arrs]) {
    return pos = +arrs;
  }

  else if (num < arr[+arrs]) {
    pos = ((+arrs));
    return pos;
  }

  else {
    return "why"
  }

}

return 0;

}

console.log(getIndexToIns([2, 20, 10], 19));
console.log(getIndexToIns([2, 5, 10], 15));