Using PHP, loop and update certain records - php

Question

Question
I have to award my members with some bonuses on completion of certain tasks.If they have achieved task1, new the task will be task2
If they have achieved task2, new the task will be task3
If they have achieved task3, new the task will be task4
If they have achieved task4, new the task will be task5
Database
while($row = mysql_fetch_array($sql))
{
$offername[] = $row['name'];
$offertask1[] = $row['task1'];
$offertask2[] = $row['task2'];
$offertask3[] = $row['task3'];
$offertask4[] = $row['task4'];
$offertask5[] = $row['task5'];
$offerprize[] = $row['prize'];
$offercurrent[] = $row['current'];
$offerpercent[] = $row['percent'];
$offertask[] = $row['task'];
}
Values:
$offername[] = (offer1, offer2, offer3 ,offerXX)
$offertask1[] = (100,150,200 ,taskxx)
$offertask2[] = (100,150,200 ,taskxx)
$offertask3[] = (100,150,200 ,taskxx)
$offertask4[] = (100,150,200 ,taskxx)
$offertask5[] = (100,150,200 ,taskxx)
$offerprize[] = (5000,2222,3333 ,taskxx)
$offertask= this will replace it value with $offertask1[]
,$offertask2[] to $offertask5[] , depending upon the condition
My Code
for ($i=0;$i<=count($offername);$i++) {
// Check for existing bonuses first. // Code omitted
//#### If it's the first bonus ########
if ($member['count'] == 0 ) {
if ($offerprize[$i] != 0) {
$offertask = array_replace($offertask, $offertask1);
$per = $offercurrent[$i]/$offertask[$i] * 100;
$offerpercent[$i] == round($per);
}
}
//### If he has claimed one bonus and this is the second bonus #####
if ($member['count'] == 1 ) {
if ($offercurrent[$i] >= $offertask1[$i] AND $offercurrent[$i] < $offertask2[$i]) {
if ($offerprize[$i] != 0) {
$offertask = array_replace($offertask, $offertask2);
$per = $offercurrent[$i]/$offertask[$i] * 100;
$offerpercent[$i] == round($per);
}
}
}
}
I have already claimed the first bonus for offer1 == offername[0]. I have tested for $offercurrent[0]. It does not work for ($member['count'] == 1) and so on.
Problem
All the values remain same for ($member['count'] == 0 ) and do not change with the count.