Failure - JLPT N3

From the mock exam 「模擬試験」my scores improved
Language Knowledge 「言語知識」up by 5%　「５％増加」
Reading 「読解」up by 10%　「１０％増加」

BUT

for Listening 「聴解」it was down by almost 20%!!! 「２０％減少」
A decrease in the listening score even after weeks more of studying after the mock exam!
What a mystery!
There was a malfunction in the playing of the exam dialogues such that two exam dialogues had to be re-played at the end. But this couldn't account the whole 20%. I think I need to devote more time to listening comprehension before the next exam, which will probably be around June.