calculation

$assigned_uid = $node->field_assigned_user[LANGUAGE_NONE][0]['target_id'];
$assigned_user = user_load($assigned_uid);
$percentage_split = $user->field_percentage_split[LANGUAGE_NONE][0]['value'];
$entity_field[0]['value'] = ((
(isset(field_get_items($entity_type, $entity, 'field_other_ins_')[0]) ? field_get_items($entity_type, $entity, 'field_other_ins_')[0]['value'] : 0) +
(isset(field_get_items($entity_type, $entity, 'field_vb')[0]) ? field_get_items($entity_type, $entity, 'field_vb')[0]['value'] : 0) +
(isset(field_get_items($entity_type, $entity, 'field_finder_s_fee')[0]) ? field_get_items($entity_type, $entity, 'field_finder_s_fee')[0]['value'] : 0) +
(isset(field_get_items($entity_type, $entity, 'field_broker_fee')[0]) ? field_get_items($entity_type, $entity, 'field_broker_fee')[0]['value'] : 0)) - (isset(field_get_items($entity_type, $entity, 'field_dlc_franchise_fee_hst')[0]) ? field_get_items($entity_type, $entity, 'field_dlc_franchise_fee_hst')[0]['value'] : 0)) * (isset(field_get_items($entity_type, $entity, 'field_percentage_split')[0]) ? field_get_items($entity_type, $entity, 'field_percentage_split')[0]['value'] : 0);