Not sure if anyone realizes this, but upkeep on heirloomed items is the same as upkeep on the normal version of the same item.
Example:
I have a Masterwork Long Espada Eslavona. After the hot-fix, it's been broken and repaired for 401 gold.
Using the figure of repair cost = 5% of base value, 401/0.05 = 8020.
Which is about the cost of a normal Long Espada Eslavona, 8026.