This calculator uses the standard formulas which were used by Archery Australia from (at least) the 1980s through to January 2011.
I have been informed that Archery Australia's handicap tables, since January 2011, are no longer based on the same formula. As such the tables which this (or any other existing) calculator generates should no longer be used for any purpose other than calculating a handicap under the old system.
See here for the current Archery Australia tables.