ChargeAmount not written for EN16931 Comfort

[PeterSawatzki-MGGM]

The following code does not write ChargeAmount if it is present obviously following PEPPOL rule PEPPOL-EN16931-R046.

ZUGFeRD-csharp/ZUGFeRD/InvoiceDescriptor23CIIWriter.cs

Lines 350 to 383 in 5c8bed7

	#region GrossPriceProductTradePrice (Comfort, Extended, XRechnung)
	bool needToWriteGrossUnitPrice = false;
	bool hasGrossUnitPrice = tradeLineItem.GrossUnitPrice.HasValue;
	bool hasAllowanceCharges = tradeLineItem.GetTradeAllowanceCharges().Count > 0;
	if ((descriptor.Profile == Profile.XRechnung) || (descriptor.Profile == Profile.XRechnung1) || (descriptor.Profile == Profile.Comfort))
	{
	// PEPPOL-EN16931-R046: For XRechnung, both must be present
	needToWriteGrossUnitPrice = hasGrossUnitPrice && hasAllowanceCharges;
	}
	else
	{
	// For other profiles, either is sufficient
	needToWriteGrossUnitPrice = hasGrossUnitPrice || hasAllowanceCharges;
	}
	if (needToWriteGrossUnitPrice)
	{
	_Writer.WriteStartElement("ram", "GrossPriceProductTradePrice", PROFILE_COMFORT_EXTENDED_XRECHNUNG);
	_writeOptionalAdaptiveAmount(_Writer, "ram", "ChargeAmount", tradeLineItem.GrossUnitPrice, 2, 4); // BT-148
	if (tradeLineItem.GrossQuantity.HasValue)
	{
	_writeElementWithAttributeWithPrefix(_Writer, "ram", "BasisQuantity", "unitCode", tradeLineItem.UnitCode.EnumToString(), _formatDecimal(tradeLineItem.GrossQuantity.Value, 4));
	}
	foreach (AbstractTradeAllowanceCharge tradeAllowanceCharge in tradeLineItem.GetTradeAllowanceCharges()) // BT-147
	{
	_WriteItemLevelAppliedTradeAllowanceCharge(_Writer, tradeAllowanceCharge);
	}
	_Writer.WriteEndElement(); // ram:GrossPriceProductTradePrice(Comfort|Extended|XRechnung)
	}
	#endregion // !GrossPriceProductTradePrice(Comfort|Extended|XRechnung)

But is this really o.k. not to write ChargeAmount ? For example the official sample

https://github.com/stephanstapel/ZUGFeRD-csharp/blob/5c8bed75474550052b1cb0851c340c8044ebddde/documentation/zugferd240en/Examples/3.%20EN16931/EN16931_Einfach/EN16931_Einfach.xml#L117C2-L147

has a ChargeAmount but no TradeAllowanceCharges. If I read this document and write it ChargeAmount is missing.

[PeterSawatzki-MGGM]

It seems that most of the samples in https://github.com/stephanstapel/ZUGFeRD-csharp/blob/5c8bed75474550052b1cb0851c340c8044ebddde/documentation/zugferd240en/Examples/3.%20EN16931 have a GrossPriceProductTradePrice/ChargeAmount set.

[stephanstapel]

yes, you could be right that this is a misinterpretation of R046.
Unfortunately, git blame doesn't work properly with such a long history of changes, so I have no idea when and why this was introduced (couldn't find a commit message, too).

[PeterSawatzki-MGGM]

I also inspected the XRECHNUNG samples and there GrossPriceProductTradePrice/ChargeAmount is not set when no TradeAllowanceCharges are present. So I think the rule does only apply to XRECHNUNG and XRECHNUNG1 but not to COMFORT. If you don't mind I will make a modifcation and a PR.