Requiring the use of our code does not prevent the use of additional codes.  It's possible to send multiple panel codes so long as the set of Observations grouped complies with all panels declared.  Our panel simply requires that at least one of our 'activity' observations are present and that when you're sending data that maps to one of our observations, you comply with our profile.  You're free to send other observations.  So if a system wishes to capture more elements and comply with a more complex panel as well as ours, they can.  They're also free to send separate grouping observations if that makes sense. We will add documentation highlighting this ability to send multiple codings and/or have more than one 'grouping' observation with some examples of how and where this might be done. We believe there's significant value in having a single 'grouping' code that all implementers of the IG can count on being used to find collections of observations about a single exercise 'episode' and therefore wish to retain our current standard code (which will likely eventually be migrated to LOINC too).