This is because you are using the same recordset to populate the title in the cart.
You could append information in the bindings for each add to cart button in order to differentiate. For instance instead of using the same value in both add to cart server behaviors:
<?php echo($row_Recordset1['Magazine_Title']); ?>
you could use:
<?php echo($row_Recordset1['Magazine_Title']); ?> 1 yr
and
<?php echo($row_Recordset1['Magazine_Title']); ?> 2 yr