You are correct Wurzel. Here's what my German dealer Bessers said,
"EU-Silver-Coin applies full 19% VAT which means that there is no difference between EU-minted coins and silver bars.
For [coins] like Maple, Eagle and all the different Australian coins applies a thing called differential charge / taxation which is absolutely below the full 19% VAT and even absolutely less than the previous tax regime."
In other words, non-EU silver coins attract VAT on dealer markup, not total price.
BUT... Bessers and other dealers I've checked are definitely keeping some of this benefit to themselves in form of higher premiums. I've checked current online prices with previous purchases made with other German dealers. They have definitely increased their premiums by about 3-5 percentage points.