Uncorrect condition
void OnItemRepair(BasePlayer player, Item item)
        {
            if (permission.UserHasPermission(player.UserIDString, perm))
            {
                item.maxCondition = 100f;//just in case the item already lost durability
                item.info.condition.maintainMaxCondition = true;//so it doesn't lose any more
            }
        }

Not all the items has max condition 100. Ex: AK

"shortname": "rifle.ak",
"condition": 150.0,
"maxCondition": 150.0,
Sure, I was just about to post here that it doesn't work for the AK. First and only item I tried.
In response to Weed ():
Sure, I was just about to post here that it doesn't work for the AK. First and only item I tried.
Ak is just example. There are variable of full condition, use it
didn't notice that, i will decompile the dlls and see how can i make it work properly 
i believe it should work just fine now, tho i can't test it as the latest oxide patch disabled the hook
Not sure if the entire server needs to be restarted, instead of just reloading the plugin, but after trying to repair an M92, repairing still results in max durability loss.
i updated it one more time, if it still doesn't work i will wait for the next oxide patch to fix the disabled hook because i cant currently test the plugin :(
Unfortunately, it seems that latest update has not fixed the issue. Tried repairing a chainsaw, various melee weapons, and a few guns.
Any updates on this looking forward to using this.
5d35f1495da0a.jpg FastBurst
Any updates on this looking forward to using this.

I taked a look and looks as hook is disabled (to track repairing, so its not working for now)

Merged post

Updated, will work on some way for now
5ba216a6d7f65.png Orange

I taked a look and looks as hook is disabled (to track repairing, so its not working for now)

Merged post

Updated, will work on some way for now

Looks like its working,
However I did notice on a couple repairs, if the Item already has red showing from a previous repair, it does not go back to 100% it keeps that value for the rest of the repairs on that item that was previouisly red.