Shakes Private Server Bug

Hello i have a bug in my server the Shield of Warriar class with 5% only can block 9/10 attacks i thinks it is impossible block all attacks with 5% how to change that

else
{
if ($type == 2)
{
if ($lvl < 10)
{
$shieldNumber = 5;
}
elseif ($lvl < 100 && $lvl > 9)
{
$shieldNumber = 10; // 10% Block
}
elseif ($lvl > 99 && $lvl < 200)
{
$shieldNumber = 20; // 20% Block
}
elseif ($lvl > 199)
{
$shieldNumber = 25; // 25% Block
}



$item ['dmg_min'] = $shieldNumber;
}


// 5% Block change the 5 to 20 its 20% block for all Player Lower 10 Level