I wouldn’t do it first and I certainly wouldn’t save it for the end. The individual IPS questions are the only questions that have any semblance of consistency on the exam. Virtually all of them follow the same approach. Solve for return, risk tolerance>>>>time passes>>>circumstances have changed, time horizon, liquidity, etc… or something to that effect.
Best case scenario, you have 25 minutes left to finish the IPS question. You’ll be tired and the last thing you’ll want to do is flip back to the first question which is likely to be the heaviest weighted question on the AM. There are far too many tricks and subtleties in the IPS questions to read with tired eyes. It’ll be the second or third question I tackle.