depends on the booking class - I guess you flew SIN-FRA on Singapore Airlines - for M, H, W you earn 75% - Maybe you were on LX on the flight from ZRH-SIN - on LX you earn 100% in booking class M,U,H

the earnings are based on the operating airline - not on the marketing airline. and it's also important to know that the booking class might get mapped on the code share airline. e.g. you have a H class ticket on LH, but H maps to W on Singapore Airlines (just an example). Mileage credit on codeshares can often be tricky to understand.