I lost 45 pds over an 11 month period. I went from 225 down to 180. The first 20 pds were easier than the second 20 pounds. I lost the first 20 in about 3-4 months. The second 20 took me the next 7-8 months to lose.

The problem is it gets harder because your metabolism will adjust to the calories you are taking in. Obviously, what you are doing is working. However the answer isn't always to cut more calories.

I would study reverse dieting. You probably are at the point where a reverse diet makes sense. Basically you increase your calories by about 50 a day. If you are eating 1400, move to 1450 a day for a week and see if you add any weight. Keep bumping that number until you see a weight gain. Hopefully you could get to 2100 a day but that is going to take some time. Once your metabolism adjusts, probably will take about 3-4 months, cut your calories back to 1800. You should start dropping pounds again.

It's like you said, "I don't want to stop doing what has worked so far". Intuitively you cut your calories to lose the weight therefore the answer to lose more weight is to cut more calories. It makes sense but your body will stop shedding fat because you go into a starvation mode. Cutting calories will only work so long.