Line 183 - Is this meant to apply to bilateral or market based transactions. No clarification was given in the document, however bilateral transactions include the costs differently than market based transactions.

The EMIX information model applies to bilateral as well as structured markets; markets may have a wide variety of market rules (which are not defined in EMIX). As such, items may be optional in the model but effectively mandatory by market rules. The mention of bilateral (lines 278 and 287) is after this issue was raise. Add text related to multiple kinds of markets as well as bilateral agreements to the introductory sections.The