I have noticed that the repair feature in the army system takes incorrect amounts of minerals. One time, I attacked someone and my Kaoser Blades dropped from 100 to 99.95. I repaired it and the repair cost me 8 minerals. Other times, a more damaged weapon uses up 0 minerals. My needle spines often uses up 0. Kaiser Blades sometimes go nuts and take 4-8 minerals after one use. This has seriousely become annoying. I propose that everyone's mineral count has three decimal places. This would help weapon repairs use up the correct amount of minerals.
You do have to remember that the more weapons of one type you have, the more minerals per point you have to pay.
It's not bugged, you just made the wrong calculations.
If you would have took the time to spy, you would have seen that he has only one of each weapons.
The more you paid for it, the more it costs to repair. I stopped playing, basicaly, since my weapons are useless. I'd gain more advantages to buy a completly new weapon rather than repairing it (costs 500 minerals only to repair).
And even if you dont have any point wasted into it, the % calculation probably consider it as 0 or more than 1 sometimes.
The thing is, it said 3 minerals per point on Kaiser Blades, the strength was 99.95. I can understand taking 8 minerals if the strength wa 97.77. It was hardly damaged. Maybe I did miscalculate. My calculator is really old after all.