The system is such that, even if WP averaged 40% all over Singapore, there's neither legal claim nor obligation to represent that 40%, only in those constituencies that they actually won above 50%. Reverse example is, George Yeo and his team also scored above 40% in Aljunied GRC, but the one that scored above 50% was LTK and his team and they won and represent the GRC. The party with more than half of the seats in Parliament forms Government and they represent Singapore on national and international levels except for constituency matters in constituencies won by opposition.
Keep harping on the percentage to representation ratio is in vain in whatever system. In non-constituency nationwide PE, TT could win Presidency by just 35%. Why don't you go and hound TCB for having given him 34% or TJS for having given him 25% that they're useless in any presidential matters after you gave them your votes?
There's no such thing as perfect political system. When the side you supports loses, blaming your side or blaming the system leads nowhere unless you're prepared for and have the manpower for uprising. Even in US system, George Bush Jr. got below 50% popular votes but above 50% electoral college votes, he could become President. Such is the US system. Al Gore fought hard for the electoral vote count but once it was there, he conceded defeat. That's gentleman. That's democracy. Not after losing, blame people, blame system, blame earth and heaven.