Journey planner to Marina Bay Sands

I have to attend a dinner at Marina Bay Sands. I tried to use the journey planner from SBS and SMRT to get to Marina Bay Sands from the Promenade or Marina Bay stations. It was quite a hassle to use these complicated planners. I do not understand why the Land Transport Authority allows these two operates to operate different websites with different structures. Perhaps LTA should build an integrated website and make it easier to use.