Hi,
It is limited intentionally for better server performance and shorter response times on large wp_post tables. 20 seemed to be more than enough for now.
You can change it via the asp_query_args filter if you need to:
add_filter("asp_query_args", "asp_query_args_change", 10, 2);
function asp_query_args_change($args, $search_id) {
if ( $search_id == -1 )
$args['posts_per_page'] = 100;
return $args;
}The $search_id should be -1 in that context, but you may have to remove that condition it if it does not work.