I agree with Paul. There is NOTHING unclear about his statement. He said, "I Raise 6000", he didn't say "I Raise to 6000 (which would have been the minimum raise. It is perfectly clear to me that he intended the 6000 to be ON-TOP of the call. In fact, if I had been at the table, I would have made him put in the 9500 total since verbal declarations are binding.
It appears Player A is trying to minimize the effect of Player B's action
Hope this helps!