Here we go again......
P1s or PICUS or P1US or any VARIATION of the same theme is semantics. They all mean the same thing the variation comes from the different log book suppliers.
For a single pilot aircraft the only time that entry can be made is on the completion of a flight test. It can't be used for the a club check or a type conversation or anyone of the myriad of other uses it seems to get put to. So Billiebobs application would have been bounced if the CAA had seen those as entries. However if he had logged them correctly they would have counted towards his licence issue either as P1 or PU2 depending on which column is the correct column for them. They would not be discarded as he wrongly claims.
The question around who logs P1 during a 28 day check is indeed an old one and open to discussion. Whatever it is it is not a PICUS, P1s, P1US etc.
Personally as an Instructor I am happy for the pilot to log P1 and I will log nothing if they are that desperate for the P1 hours. Other Instructors I know do not take this approach claiming if they are in the aircraft and 'working' they are P1 so the other is PUT even if getting no Instruction. I am not going to enter into the debate on this one....