When you are multiplying and dividing the order of the multipliers doesn't matter. For instance, 5 x 3 x 2 is the same as 2 x 3 x 5. So the order is immaterial. You might want to check those calculations where the answer changed depending on the factoring sequence.
Check your landing safety factor, for propeller-driven aircraft it is conventionally rounded to 1.43. Current exam questions are much better phrased than older ones, so if they want the data straight out of the graph for Class B they tend to ask for it. If they want factors to be applied it is (usually) clear enough.