vix41The key is to stick with the method that you can consistently follow in the exam. Honestly, I cannot be bothered with memorizing a table. I know from experience that once the exam starts, all this goes out of the window. I prefer to just do a quick calculation in the mind, and this is pretty simple. Plus, I may do it at different points depending on my internal gauge of my overall progress. Also, when I see I am a bit behind time, I may speed up on the easy ones, meaning do the operations and computations faster. Of course, there is a danger of making a simple mistake somewhere but when you are running out of time, you have no choice but to compensate somehow.
In summary, stick with the timing method that works for you. Perhaps others can share what works best for them.
Cheers,
Dabral