[EUGEN-T10-R019]-Total payable amount in an invoice MUST NOT be negative [EUGEN-T10-R009]-If the category for VAT is exempt (E) then an exemption reason SHOULD be provided. [EUGEN-T10-R008]-For each tax subcategory the category ID and the applicable tax percentage MUST be provided. [EUGEN-T10-R001]-A supplier postal address in an invoice SHOULD contain at least, Street name and number, city name, zip code and country code. [EUGEN-T10-R004]-If the payment means are international account transfer and the account id is IBAN then the financial institution should be identified by using the BIC id. [EUGEN-T10-R020]-If the invoice refers to a period, the period MUST have an start date. [EUGEN-T10-R021]-If the invoice refers to a period, the period MUST have an end date. [EUGEN-T10-R003]-Each invoice line SHOULD contain the quantity and unit of measure [EUGEN-T10-R007]-If the VAT total amount in an invoice exists it MUST contain the suppliers VAT number. [EUGEN-T10-R010]-If payee information is provided then the payee name MUST be specified. [EUGEN-T10-R015]-IF VAT = "AE" (reverse charge) THEN it MUST contain Supplier VAT id and Customer VAT [EUGEN-T10-R016]-IF VAT = "AE" (reverse charge) THEN VAT MAY NOT contain other VAT categories. [EUGEN-T10-R017]-IF VAT = "AE" (reverse charge) THEN The taxable amount MUST equal the invoice total without VAT amount. [EUGEN-T10-R018]-IF VAT = "AE" (reverse charge) THEN VAT tax amount MUST be zero. [EUGEN-T10-R024]-Currency Identifier MUST be in stated in the currency stated on header level. [EUGEN-T10-R005]-A Delivery address in an invoice SHOULD contain at least, city, zip code and country code. [EUGEN-T10-R002]-A customer postal address in an invoice SHOULD contain at least, Street name and number, city name, zip code and country code. [EUGEN-T10-R011]-If the VAT total amount in an invoice exists then each invoice line item MUST have a VAT category ID. [EUGEN-T10-R006]-If the VAT total amount in an invoice exists then an Allowances Charges amount on document level MUST have Tax category for VAT. [EUGEN-T10-R022]-An allowance or charge amount MUST NOT be negative. [EUGEN-T10-R023]-AllowanceChargeReason text SHOULD be specified for all allowances and charges [EUGEN-T10-R012]-An allowance percentage MUST NOT be negative. [EUGEN-T10-R013]-In allowances, both or none of percentage and base amount SHOULD be provided