[iqanq]

I know how VAT works. If the government changes the VAT overnight then prices won't round to .99 until merchants (or Amazon themselves) change the base price again. I don't see the issue.

[germanier]

Usually in B2C prices are quoted and agreed upon as gross price (including tax). If the tax rate is lowered, this then raises the base price.

[eru]

I mentioned this, because American retail prices as quoted typically don't include their equivalent of VAT.