The explanation of the buff is: "Reduces troop upkeep by 5%. Can be stacked up to 20 times. Each buff lasts 24 hours."

This means to me, 20 clicks = 100% upkeep reduction. (5% * 20 = 100%)

If they want the reduction to be 50% max, so be it. However, they should change the text on the buff icon and announce the change.

This is important. The amount of troop upkeep reduction I can get determines how many troops I can keep around or build. I shouldn't have to log on, start clicking and realize that after 10 clicks my troop upkeep has quit going down.