40% protein 40% carbs 20% fat good percentages to drop body fat and get abs?

The thing that matters is the amount of calories you get daily. Calorie is a calorie no matter if it comes from protein, carbs or fat. Simply it's in different form.

Percentages are arbitrary, and are useless in most circumstances. Instead you start by determining your protein needs-there's a ton of opinions out there, but the most common one when losing weight and maintaining lean mass is about 1g per pound of total weight. So you start with 200g protein, 800 calories. Next is fat, another one that everyone has a strong opinion on. A good number to target would be 0.5g per pound lean mass, so (200*.84)/2=84g, 756 calories.

So if your target calories now is 2750, subtract the protein and fat calories of 1556 and you have 1194 remaining, 298g or so of carbs. It's this last number that can vary based on activity. If you do no cardio, then you need less carbs and the 298 goes down. If you do 3 hours a day your carbs need to go way up to fuel that activity.

Since total calories will vary based on activity, the % of each macro will change since it depends on your total. That's why a fixed 40/40/20 plan doesn't make sense. but it can be convenient if you plan your meals to all be in some zone diet system, you'll just be getting more or less protein and fat when it's carbs that you need to adjust.

If 2750 is your maintenance calories based on activity, then you can lower that by 10-20% to create the deficit that will let you lose fat over time, and you only tweak the carb intake. I hope that helps.