The base of seblak is kerupuk, and people forget that kerupuk is fried starch even after it has been soaked. 80g of rehydrated crackers, which is a normal scoop, is about 150 calories. The kencur paste is fried in oil first, and the egg goes into that oil, so the base bowl with egg and paste is already 260 before any topping. FatSecret's 262 figure is basically that bowl.
Then the toppings, and this is where seblak gets its reputation. Macaroni 50g is 60. Two bakso are 60. One sosis is 70. A handful of mie is 100. Ceker is about 50 for two. Sosis, bakso, and mie together is 230 on top of the base, and a full seblak with everything is 600 to 650. The Rp 15,000 to 20,000 komplit at a normal stall lands around 450 with egg, macaroni, bakso and sosis.
Level pedas changes nothing. Level 5 and level 1 are the same calories, the chili is free. What is not free is the oil the paste is fried in, about 5g per bowl, and the extra spoon of oil some stalls add for shine, another 45. If your seblak has a red oil ring around the edge, that ring is 50 calories.
The protein is weak. 16g in a 450 calorie bowl, most from the egg and bakso, because kerupuk has none. That is why seblak does not hold you and why people order it as a snack and then eat dinner two hours later.