That is the sort of thing one wants to meticulously log, and get the instructor's signature next to each such flight just to make sure nobody can argue with it.
Couldn't agree more, I have a ton of signatures in my logbook.
I log all dual flight in the UK (and G registered aeroplanes) as DUAL (PUT) and all dual flights in the USA (and N registered aeroplanes that I am rated for which is anything under 12501 lbs unless it is turbojet) as PIC as well as DUAL.
I ensure that I meet any requirements for JAA seperately from the FAA regs, I was going to start two logbooks ages ago, but it is beyond that now, so I ensure that whenever I have contact with the CAA or have to fill out CAA forms, that I only include their requirements (i.e. FAA PIC/Dual flights get filled in as PUT).......I only bother to log cross country if >50nm, and I don't bother to log "IFR" flights, only Actual or simulated.