I don't think this is particularly strange really. The way I see it, when I am flying in IMC in a G-Reg, I am doing so on the basis of my IMC. The fact that the IMC was issued on the back of the FAA IR is not important and its validity is not dependent on the IR. All the FAA IR did was exempt me from the IMC test - I paid my £67 and got a standalone rating on my JAA PPL.
When flying on my IMC, I am subject to its validity requirements, which don't require a safety pilot after 6 months.
And
AFAIK, all approaches anywhere in anything SEL count for FAA IR SEL purposes. So each time I did an approach, it would count towards my 6 approaches currency.
That said, last time I went for more than a few months without an approach, I got a lesson before I went up in IMC again. Its the safe option.