The 20 points difference is from the United Cup 70 against 90 - with 35 points for defeating Tomljanovic against 15 on Coric
Tx
Strangely enough. and against my expectations, Katie B has been awarded 90 points by the WTA. On looking at the Untied Cup website I found the phrase "Rankinging for the Tournament" insteaed of WR - so it means they use that.
Useful to know for next year - unless it changes again.