I don't know how your BLS measures job +/-, but if it's anything similar to how the ONS does it, it's no wonder the numbers are always crooked.
The ONS does it by phoning a limited number of businesses and asking them what's the price of these certain X items, as opposed to anything digital/mass data.
It's basically the same of how they do political polling - call up registered voters and ask them, which obviously skews it as only a certain subset of people register, and then a smaller set actually pick up the phone.
