As I understand, "performance based" here means choosing the best code snippet to insert on line X which gets the job done (or similar). Actually, a lot of the questions in my book and in the online mock exam have always been in this style. Some are drag and drop and supply an exhibit with certain lines omitted - the idea is to select the correct lines to be dropped in the correct places - and sometimes there are more choices to drag than lines to drop in (requiring careful selection of lines and not just elimination). So you really have to choose very carefully the code fragments which get the job done in the right places. Some of my multiple choice questions ask which line of code is best inserted on line X to achieve goal Y etc. So there are a lot of those more involved questions in there. We've had a lot of feedback to say the book questions and online mock exam are very challenging, but as I've always said, they are designed to get you thinking so the exam seems straightforward, by comparison.
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )