WoW Function wrong return result – equipment autorepair addons don’t work

This function:
https://warcraft.wiki.gg/wiki/API:GetRepairAllCost
GetRepairAllCost() should return values when equipment is damaged and merchant window is opened.
Without it Auto repair addons don’t work.

Tested with:
/script local a,b=GetRepairAllCost();DEFAULT_CHAT_FRAME:AddMessage(a..” “..tostring(b))
Broken equipment should return some value greater than 0 for a – it currently doesn’t – returns 0 all the time.