Hi,
just to be sure, you used regular tool to repair a 88/92 shotgun, and after successful repair it went to 82/82.
Correct...
That means: "successful maintenance will repair an item to max condition"
Wait, no, that's not what it means, it's never meant that.
and "at the same time it will decrease overall max condition by 8-10%"...which it did.
Well, that's what's happening, except that means the maintenance was a failure. (Actually, I've seen "maintence failed"s that didn't end up that bad...)
The 88/92 shottie went to 82/82, max condition was 92% minus 10% because of using a tool gives 82%. So because of using a tool the new max condition is set to 82%.
Explain, very slowly (because I want you to understand the words you're using), how "Successful Maintenance" results in a weapon that's in WORSE shape NOW, than it was BEFORE you "repaired" it.
Sure, some times it seems like the condition after repairing is worse than expected, but by using a super toolbox (you can buy it from Rondo in NCR or farm it from GR mutie quest) you get much better results than fixing it with a tool.
Also it's better to use super toolbox because there is a 20% chance that max condition will not be decreased.
Meaning your shotgun would stay 92/92 even after repair.
That's not relevant, read this SLOWLY and answer this (really quite simple) question:
"How does "Successful Maintenance" result in a weapon that's in WORSE shape NOW, than it was BEFORE you "repaired" it?" That's not possible.
So either it's a defect in game construction, meaning the devs SERIOUSLY fucked up, or it's an moderately common bug, probably caused by the algorithms for repair.
(Now, unlike some people, take a moment, THINK carefully, and you might just get the issue.)