Help with math please?

Yes, this seems right if by "sedentary" TDEE you mean all the calories you need to maintain at your normal activity level BEFORE intentional exercise calories.

Your calories ingested (1375/day) plus your burn of stored calories (i.e., weight loss, in your case, 1073/day) = 2448 cals/day required for maintenance at your activity level during this period, which includes an average of 225 cals/day of intentional exercise. Or if you want a maintenance number that you would add your daily exercise calories to, the way that MFP is set up to do, it would be 1150 net cals/day + 1073 calories burned from body storage each day = 2223. Then of course you subtract 500 calories from that number to get a daily calorie goal, if you wanted to lose a pound a week, for example.

I recalculate my "before exercise" maintenance number every week, based on data from the preceding eight weeks, and consistently get a higher "before exercise" daily burn number than MFP calculates. I don't think I'm a special snowflake either, but I don't believe that everybody's activity level magically falls at one of the four levels that MFP uses --I think it's a line (or curve) that people can fall anywhere on (i.e., you might be on the heavy side of lightly active, or the light side of moderately active etc.)

Plus, I doubt that the part of the formula that adjusts for your age is spot on for everybody; people's biological age might be off from their chronological age, and for women I have to think the formula makes an assumption about menopause that is based on the age you plug in, and that assumption might not be accurate for you. (The government age-based micronutrient reference values seem to assume all women are post-menopausal by 50, since iron recommendations decrease at that age.) The alternative to the discrepancy being inaccuracy in the formula is that I have a fairly consistent bias in my logging of calories consumed and/or exercise calories expended in the opposite direction from what seem to be most people's error tendency, which would make me another sort of special snowflake. I'm pretty obsessive about weighing food at home, and because I cook a lot I think I'm pretty good at figuring out amounts and ingredients of foods I eat at restaurants, etc.

I am a 51 year-old woman, 5'4" and currently weigh about 10 kg more than you, and my "before exercise" maintenance number (what you're calling "sedentary" TDEE I think) was just under 2192 at my last calculation -- very close to your 2223. (I guess my extra weight and half-dozen fewer years don't quite make up for your three extra inches of height.)

I agree with Neline and would also add that the 3500 cals = 1 lbs only applies when only FAT is lost. This is because one lb of muscle has significantly less calories than a lb of fat. You can't assume you've only lost fat, you might also have lost some muscle mass, as is common in weight loss. This can throw off your calculations as well. Just keep doing what you're doing, it appears to be working.

What is about 2200 that seems incorrect?