it's about method, not about numbers.
sorry to give different assumptions. The reason was that in the original numbers, people can argue with A and D, A means 5% earning, D means 5% borrowing. It's hard to say which one is better, while your method gave 2 very different numbers: 5% vs 195%.
I changed it to both 15%, then it's kind of common sense that A is better than D. 15% earning is better than 15% borrowing, while your method gave 2 very different numbers: 15% vs 185%, and strongly favored D instead of common sense A.
That's the reason I changed the number, but not the game. The game is still the same. Changing numbers made the points clearer.
Thanks for your valuable points.
