Correct, the time is logged according to the FARS which state you log PIC....
Why? Becasue you're already rated and current on type, therefore you are entitled to log PIC. Note though, if you are conducting instrument training, the minute you enter real IMC, you can no longer log PIC, as you no longer rated to be there.
If training for a ME rating (not sure about the sea plane rating)which you don't have, you obviously cannot log PIC as you're not already qualified.
However if conducting instrument training for an FAA IR, in a G reg plane, with an FAA (and JAA dual qualified) instructor, you must log the time according to the CAA....
[editied cause I just re-read your post]
Under the FARs all sucessful flight tests are logged as PIC.
EA