They are absolutely different by office! Moreover, they're different by timing as well. Think of these as constantly change and in flux (number of questions, amount of time, etc.). That said, you shouldn't really worry about this.
Can you predict what case you will get? Nope. Do you let this bother you? Nope :)
Same thing applies here! Just learn the approach and practice the skills required.
The best way is to really find online tests / questions and practice. Regardless as to whether is a new or old test, the principles are mostly the same:
- Time management (need to think quick)
- Business knowledge/context (incl key formulas)
- Critical thinking (answers that are very similar to each other...clues "hidden" in the text)
- Ability to interpret data/charts
Think of it as a merge of a case and the GMAT/GRE.
You need to be clear on some key case-related and account formulas (margin, growth, breakeven, etc) as well as be good at critically understanding the question (including nuance to questions) and parsing through complicated text with a fair amount of distraction.
You'll also need to be good at chart/graph reading.
The (old) McKinsey PST, BCG Online Test, Bain SOVA test, etc. are all quite similar so leverage resources across all of them.