it's not a different policy, do you know what VAT stands for ? It's not difficult, the tax is added to the original price, not deducted from the final tax-inclusive price. This isn't a sale discount.
got it. that would make sense since 56/340 ≈ 16.7
although this still strictly counts as financial iliteracy (ignorance of the meaning of 'vat') rather than 'innumeracy' (ignorance of how to do math) though ...