Reading Revs Rant, it does seem confusing
However, I thought SFI2 had been available as an option for a couple of years, but with SFI2 you could just chose which module you wanted BT to check and thereby giving the ISP more choice as to pinpoint what they want Openreach to check. So for example if the ISP suspected it was the EU internal wiring then they could just order the wiring model. The cost for this is less than the full SFI1 service, therefore ISP supposedly billed for just the modules they order. irrc one of the modules is Network, which just requests things like pair quality and nothing at the EU premises.
AFAIK ISPs can still use the old full SFI if they wish which is fixed cost, but if say the fault was found to be EU wiring then the ISP would be charged the full rate.
So it does seem like there is some confusion somewhere regarding terminology and no reason why the SP still cant order the old full monty as SFI(1). I'd assumed SFI(2) would mostly be used in those cases where the EU may have a problem which requires BT to sort out things like Internal wiring or the modem and the charge would be passed back to the SP for possible billing to the EU.... or am I missing the point of the rant?