The satay sauce is the dish, and it is also 40 percent of the calories. A hawker ladle is about 80g of ground peanuts, oil, chilli, sugar and tamarind, which is roughly 190 calories. The bee hoon underneath is 165 for 150g. Everything else on the plate is light. Cuttlefish and cockles are around 50 calories for 50g, the pork slices 55, and the kangkong and bean sprouts about 10. A 462 calorie plate that is mostly sauce and noodles.
Bee hoon is the noodle that helps you here. It is thin rice vermicelli, so a full plate by volume weighs less than the same plate of yellow noodles. If this were satay yellow mee it would be closer to 520. The stall is doing you a favour without meaning to.
The problem is extra sauce. It is normal to ask for more because the plate dries out fast, and a second ladle is another 190 calories. A S$5 plate with extra sauce and extra cuttlefish lands at about 600. If you want more flavour, ask for more chilli, which is 10 calories, not more sauce.