Please find a couple more calculators below. They vary slightly, for example:
From Helsinki (HEL) to Shanghai (PVG):
4604 miles
http://gc.kls2.com/
4604 miles
http://www.milemaven.com/
4570 miles
http://www.webflyer.com/travel/milemarker/
4580 miles
http://www.mapcrow.info/cgi-bin/citi...city2=&cntry2=
However, for the above flight Iberia (oneworld) only gave me 80 points (between 3001 to 4500 miles). Is there objective any way to complain?