A) If you're using a construction heuristics and there are 1 billion planning values, it's not efficient to try all for every step of FIRST_FIT.
B) If you're using 5 planning variables with each 1000 planning values, you don't want a Cartesian product of every combination (= 1 000 000 000 000 000 CH moves), but want to schedule them individually (= 5 000 CH moves).

Solution: make all that stuff configurable with good defaults out-of-the-box.