Sharpshot I hold both SEP & MEP class ratings & fly both single & twins regularly.
However, the experience required for revalidation, seems to me to be totally illogical .... but that is JAR for you!
For the year 2002, I am in the first year of the SEP 2 year cycle, so I do not need to fly a SEP AT ALL! But in 2003 I must do 12 hours of otherwise pass a SEP proficiency test.
In 2002, (just to be perverse
) I have done more SEP time than MEP & may not quite get the 10 "route sectors" in my logbook, before my annual MEP test in December.
But as previous posters have said, this does not matter. A route sector is only 15 minutes in the cruise, plus a circuit join & landing. At Elstree, as for many small aircfields around London, it takes 10 to 15 mins, just to get to the local training area, where we can get away from the London TMA, & climb above 2500' to do the upper air work bit of the test. So, in practice, all I have to do is tell the examiner that I have not quite got the 10 sectors, & would he please test me over the one sector that we will be doing anyway!
As for you question on cross-crediting .... there ain't none! This summer I have done lots on long cross countries in SEPs including to France, but none of these count towards the MEP sectors.
The only small concession that the examiner told me about last year, was that my MEP test, doubles as the one hour instructional flight for the SEP. So we can save that cost.