Otta
Have a look at your exam technique.
Do what 34R said and allocate time to each mark. For example I think I worked it out to be around 3 - 3.5 min per mark so that is close to 20min per Flight plan.
A technique that I used was to start with a one marker and then one or two, 2 markers to get the brain into gear. Then I would launch into the five mark q's and then the four Mark q's and so on.
I did this so I had already got the big marks on the board first and then I was not under pressure whilst doing the 5 mark (10% of the exam questions).
It took me a few goes to get it, which is nothing unusual for most people when it comes to Flight Planning.
Ash767