Why is it more likely for an MBTI IxxP to end up as a socionics IxxJ, than for an MBTI IxxJ to end up as a socionics IxxP? Why are type descriptions for introverts in the socionics domain pretty much the same as those for introverts in the MBTI domain, with the exception of INxx?

ExxP -> Exxp
ExxJ -> Exxj

ISTJ -> ISTj
ISTP -> ISTp
ISFJ -> ISFj
ISFP -> ISFp

INTJ -> INTp
INTP -> INTj
INFJ -> INFj more than INFp
INFP -> INFp more than INFj

Annoyed. I don't need to be special.