To my points: The formal written disclosures as to groupings is relatively new. Hence our need to get a timeline here. Prior to formal, written grouping disclosures were required, there wasn't any mechanism to disclose one's grouped activities. See Rev Proc 2010-13 as to this point. Formal groupings were required for new groups for tax years beginning on or after 1/25/10. So, you might be in a situation where a formal grouping disclosure was not required. In which case, based on how the taxpayer reported things on his 1040 over the years, it might be that we can legitimately argue that a grouping election has already been made. In which case, we put the late election relief in our back pocket, since it wouldn't be needed at this point.
And do note: There is a very good reason why the Rev Proc was issued: Because the IRS had no real way of knowing what the taxpayer grouped and didn't group. So, if our activities took place before formal groups were required to be disclosed, we have a very good case here, assuming we netting things on Schedule E, Page 2 in some fashion over the years. The fact that the IRS issued the Rev Proc is in our favor in my view. It evidences the fact that the IRS couldn't totally tell what was and wasn't grouped. Therefore, the taxpayer's own stipulations here, and how he reported things, carry some weight.
We discussed this issue extensively on TA one time. I think it was JAD or Wiles that started the thread...
My next point was about the appropriateness of the grouping. That is, even if we successfully assert that we have properly grouped the two activities, the question remains: Was it appropriate and were we allowed to do it? This gets to Dave's points. Hold off on the proportionate ownership test. What we need to look at here, in detail, is the Substantiality issue. There is some case law on this and the fact that we have a big loss may or may not fit into the mix here. There are quantitative and qualitative factors that need to be examined.