So, I used to use this kind code:
$form['fields']['1']['defaultValue']=$current_user->data->user_email;
$form['fields']['0']['defaultValue']['1.3']=$user_info->user_firstname;
$form['fields']['0']['defaultValue']['1.6']=$user_info->user_lastname;
$form['fields']['2']['defaultValue']=get_user_meta( $current_user->ID, 'bedrijfsnaam', true );
$form['fields']['3']['defaultValue']['4.1']=get_user_meta( $current_user->ID, 'straatnaam', true );
$form['fields']['3']['defaultValue']['4.3']=get_user_meta( $current_user->ID, 'postcode', true );
$form['fields']['3']['defaultValue']['4.5']=get_user_meta( $current_user->ID, 'plaats', true );
Which works perfect until you change around the order of the fields for example. It was intuitive to me, but not supported I guess.
What I would like is that the field number would not be incremental. Now the first is $form['fields']['0'], the second is $form['fields']['1'], etc. But would get the ID of the field.