I doubt whether they will expend much effort on IR(R) conversions until both the EIR and C-B IR have been passed to the comitology stage - otherwise the work could well have proven to be nugatory.
Certainly much more attractive to convert after the much reduced TK requirement of the EIR/CBM-IR is established. But I can't see why an upgrade route of some sort couldn't be offered. Anyway, it seems Cliff saw it your way. The CBM-IR should offer a sensible upgrade route in due course.