Spanish ATC
 

I have done an advanced search with no results for what is I guess quite a popular query since the dawn of ATC.

What is the reason why the spanish and one or two others switch the flight levels around ie westerly magnetic track odd flight levels when i expect even and viser verser. I thought we were all on one hymn sheet these days?

thanks experts

No idea which routes you are talking about, but a glance at an en-route chart will show you that 'non-standard' levels on airways are not uncommon everywhere including UK.

This is common in several European FIRs were airways change directions around North. A mainstream has been established from the Canaries up to Northern Europe that is entirely even level northbound, though the majority of the legs is magnetic East. What's the problem about it?