I have noticed some issues with the 2 mock exams that come along K&B book.
1. There are some questions having multiple answers,mentions to "Choose all that apply", but are provided with radio buttons.
2. For some questions even if you select correct answers(correct as per references mentioned there as well as my knowledge), it says incorrect.
3. Pass mark in real exam is 59%, In mock even when I get 70% it says Grade Fail. I think it doesn't weight questions equally either.
As per my personal opinion, I don't find the mock test interface very friendly, mainly because even the codes are written in plain fonts, and that many of them don't fit in single screen. I don't know how things are on real exams.
However I still believe that K&B is the BEST book for the purpose. They just need to improve on with the mocks.
May be I am expecting a bit too much from the "free stuffs".