ça me parait une usine à gaz.

<?php
$Tab=array(2.3, 1.4, 6.3, 7.2, 5.6, 1.9, 7.8, 2.2);
sort($Tab);
echo $Tab[0] . '<br />';
echo $Tab[1] . '<br />'; 
?>

<?php
$Tab=array(2.3, 1.4, 6.3, 7.2, 5.6, 1.9, 7.8, 2.2);
sort($Tab);
echo $Tab[0] . '<br />';
echo $Tab[1] . '<br />'; 
?>

$Min1 = min(array ($result_Coef_HtP, $result_Coef_Dt));
//echo (($Min1)."\n>");
$Min2 = min(array ($result_Coef_Cp, $result_Coef_Ab));
//echo (($Min2)."\n>");
$Min3 = min(array ($result_Coef_Org, $result_Coef_Main));
//echo (($Min3)."\n>");

$tri = array($Min1,$Min2,$Min3);
    
    sort($tri);
    unset($tri[2]);
    //print_r($tri)."\n-------";
$tri0 = ($tri[0]);
$tri1 = ($tri[1]);

echo $tri0."\n>";
echo $tri1."\n>";

$Tab=array($result_Coef_HtP, $result_Coef_Dt, $result_Coef_Cp, $result_Coef_Ab, $result_Coef_Org, $result_Coef_Main);
asort($Tab);
foreach( $Tab as $value ) 

  //echo $value . '<br />'; 
  echo '<br><br>';
  echo $Tab[0] . '<br />';
  echo $Tab[1] . '<br />'; 

$i = 0;
foreach($a => $b){
   $i++;
   if($i < 3){
      //tu récupère tes variables
   }
}

$Tab=array($result_Coef_HtP, $result_Coef_Dt, $result_Coef_Cp, $result_Coef_Ab, $result_Coef_Org, $result_Coef_Main);
asort($Tab);
foreach( $Tab as $value ) 
  echo $value . '<br />';

$Tab=array($result_Coef_HtP, $result_Coef_Dt, $result_Coef_Cp, $result_Coef_Ab, $result_Coef_Org, $result_Coef_Main);
asort($Tab);
foreach ($Tab as $key => $val)
{
echo "$key = $val\n";
}

$Min1 = min(array ($result_Coef_HtP, $result_Coef_Dt, $result_Coef_Cp, $result_Coef_Ab, $result_Coef_Org, $result_Coef_Main));
echo("plus petit coef:" .$Min1);