IIFYM?

I was reading up on this when I was looking for a TDEE calculation and I used the calculator provided there but the numbers seem high lol

some stats

Female
34ish (will be 34 in Aug)
5'9" tall
262lbs (but I do carry a lot of muscle)
was sedentary but I am now swimming 5-7 days a week (not sure how to classify the swims but it isn't just swimming back and forth, I do sets where I swim at 85-100% effort - varies by set - and rest between 50s or 100s about 10-90secs depending on the set. Currently hitting about 1.7km in an hour but working up to 3 or 4km in an hour)

Also doing some strength training but mostly at home for now

The IIFYM thing intrigues me but the numbers seem high? Their calculator gave me:
CARBS PROTEIN FAT FIBER CALORIES
GRAMS per day 67.2 262 117.9 52 - 66 2378
GRAMS per meal 16.8 65.5 29.5 13 - 17 595

Couple of questions:
-do these numbers seem high? 262g of protein? really?
-are people successful doing IIFYM.?
-are there better macro ratios to use?

I am just starting this process and I am good with the exercise and working out and even doing weights but in the past when I was working out I did not pay attention to "macros" and I could use some help :)

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