Wally- The radio procedures for minimum fuel calls have changed since late 2012.
In a nut shell - If you think you will go below Fixed reserves you call "Minimum Fuel". If you know you are going below - you call "Mayday". Pan call is not now utilised in a min fuel situation.
Here is a link to the IFALPA brief on the matter for you.
http://aviation.osu.edu/wp-content/u...gency-fuel.pdf