Ok that makes sense. That snippet on works for the Event Tickets Plus.
Try out this instead:
if(class_exists('Tribe__Events__Tickets__Woo__Main')) {
remove_action( 'tribe_events_single_event_after_the_meta', array( TribeWooTickets::get_instance(), 'front_end_tickets_form'), 5 );
}
if(class_exists('Tribe__Events__Tickets__Woo__Main')) {
add_action( 'tribe_events_single_event_before_the_content', array( TribeWooTickets::get_instance(), 'front_end_tickets_form') );
}