[Illidan]

The 3% consumer tax was introduced in 1989, so the 2920+tax price is definitely wrong.

When the consumer tax was introduced labels had to change the price on their releases, but that doesn't necessarily mean they had to change the catalog or the JAN, so it can happen to have the same release with different prices. For the entry price, we only consider the original one.
In this case it would probably be hard to find a release with the original price since they were around only for a few months before being changed.