Autoinvoice import is slow per R12 upgrade - tuning options

After researching on the performance for the Autoinvoice Import tuning - running out of options. Autoinvoice Import Program runs slow per R12 upgrade (even for 1 transaction to process) - what are the tuning options? For instance, raaebt - calc tax - going to the business tax engine and takes some extra time - we do not send tax lines and only putting 1 tax line manually and could save time by 'turning off' the raaebt - is there flag/profile/option to do that, is it possible something like that? Any help is appreciated.