Haven't had the chance to scrutinise the quotation, but I understand from your t-blog tread that you are doing quite a fair bit right?  Tearing down walls, hacking and creating island kitchen etc.  Looks like quite market price liao.  Can't complain.  From experience, I realised it's 'a penny for quality'.  Sometimes they might quote you lower, but the quality of the finishing might be a bit different, right down to the laminates, the carpentry, the ceiling works, etc.  Even the door frames, handles can vary quite a bit in quality.