Let's take a close look at what really happened
First off the amt WP proposed wasn't that different
2ndly the approach on the principles of how to formulate the salary by WP was different but because of the massive screw up used in the formula, the principle ended up almost the same, that of which to peg to private sector income earnings
Finally, after getting totally pwn by PAP in parliament and made a mockery of their own manifesto by changing their stance multiple times, they still voted against the bill.
In real life we call these pple hypocrites