Yes. it gets harder as you approach you "ideal" weight, partly because you have to adjust to changes in your base metabolic rate. As you get lighter, you need less food to maintain your new weight.
The biggest thing, though, is that you have given up smoking. Congrats for that. It is even more important than losing the weight and certainly more important than losing the last few pounds above 180. And the fact that you have managed to continue losing weight while giving up smoking is a real achievement, most people fail at that point.
Don't expect to maintain a weight loss of 10lbs per month; in fact don't try. You'll be better off in the long run losing the next 25 lbs at about half that rate, it'll give you time to adjust gradually to a level of exercise, and eating habits, that you can sustain indefinitely in order to keep the weight off. People who lose the weight very fast have a tendency to gain some of it back very fast, too.