Utility function is supposed to contain only terminal values. You're not supposed to factor instrumental values into your utility function.

Utility functions are typically defined over expected futures. A feature of that future is how many seconds and calories you spent making decisions (and thus not doing other things). And so if a gamble will give you either zero or a hundred calories, but take fifty calories to recompute all of your plans that depend on whether or not you win the gamble, then it's actually a gamble between -50 and 50 calories, not 0 and 100.

In short, utility functions should take terminal values as inputs, but those terminal values depend on instrumental values, and your utility function should respond to that dependence.