Check if your Bosch dealer have a battery checker like this Bosch Battery Capacity Tester , if they do have it they will print a report like in the picture.
0275007544 is vertical, 0275007546 is horizontal, so DON'T BUY IT, it will not fit.
Please tell me how you figured out that battery lost 20%? I have 17000Km and i can't tell any difference.