Since there is a very small window for that last fertilizer drop to be effective you should be using fast release instead of slow. Your last mowing should be as short as possible without scalping the lawn, 1.5-2 inches is my last cut.

Ok, I'll go down to 2 inches then, I just feel weird going lower than that, it's been bred out of me I guess to cut short thanks to forums like this :-).

I thought the slow release was best so that the nitrogen is there & ready for the spring green-up.

If you want your grass to get fertilizer in the spring, apply it in the spring. Slow release fertilizer will be wasted on your dormant grass throughout the winter and early spring. The late fall drop benefits your roots and carbohydrate storage, but it needs to get to the plant before soil temps drop too low, when the grass plant is totally dormant. Also your lawn doesn't need a lot of nitrogen in early spring. Most people recommend your first big nitrogen drop for cool season grass around labor day. Organics provide a slow and steady source of nitrogen in the early spring, as well as beneficial organic matter, so you might want to try that early next spring.