PoHate was revamped roughly a year ago. It appears as though they replaced the whole zone with a "new" one (whole new graphics files and all that stuff). To maintain version control or ensure that no old files conflicted with new ones, they named this revamped version hateplaneb.
PoHate A will refer to the old zone (2 levels, KoS port in, weak walls with chain aggro, raid force zone mainly) and PoHate B is the new one (safe ZI, single groupable, faster repops, etc).
Inny and all his friends are in PoHate B as A is no longer accessible.