...
After considering the "plus" types, it seems that only these three would "convert" to a particular error (or, an error involving a PtoP template):
P1("The relationship between the particular referred to by the IUI and "
+ "the particular in question does not hold during the stated time "
+ "period"),P2("The UUI for the particular does not refer to the intended particular or "
+ "it refers to no particular at all"),P3("There is an A1 error in the corresponding A-tuple; the PtoP-tuple is "
+ "nonsensical"),
...