Interesting plugin. I just activated so not tested much yet. I develop/test with all debugs on. Thought you might like to know the plugin generates a warning.
Warning: Call-time pass-by-reference has been deprecated; If you would like to pass it by reference, modify the declaration of [runtime function name](). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file in C:\web\wpbeta\wp\wp-content\plugins\table-of-contents-plus\toc.php on line 996