This video convinces me that Tan Boon Heong's record probably had errors in it. Fu Hai Feng's 285 here makes sense. He probably wasn't fully warm and not aggressive unlike in a match, where he might hit a little higher (29x). I firmly believe that if you put Tan Boon Heong here, he would hit around 280-290, same with the other top players that are the big smashers.
Lee Chong Wei (Malaysia) 408km/h (Hong Kong Open 2015) Jan O Jorgensen (Denmark) 407km/h (Malaysia Open 2016) Viktor Axelsen (Denmark) 404km/h (Japan Open 2015) Parupalli Kashyap (India) 401km/h (Japan Open 2015) Lin Dan (China) 401km/h (Japan Open 2015)