Sorry, thoughtless copy-paste mistake in the .sh3f / PluginFurnitureCatalog.properties above.

[font=courier new]price#2=2.50
currency#2=EUR
[s]value_added_tax_percentage#2=14[/s][/font]

It should have been:
[font=courier new]price#2=2.50
currency#2=EUR
valueAddedTaxPercentage#2=0.14[/font]

ok