more than european, asecna too
Read the small print.
France, Iberia, West Med, North Africa, French-Speaking Africa do tend to favour the Evens North Odds South. So the UK, AENA, ASECNA and the EUR/SAM corridor I think file differences and have consistency at least from about Conakry Northwards.
It may be that at some point the levels were chosen to favour those going South agin the wind. For there are Northbound routes that swing hemispheres to allow Southbound travellers to hold the weather advantage and have the shorter route. Consistency of level and directions is therefore important.
Examples. VFA-ARE-ORTAC is a Northbound route all one hemisphere. But how about BAROK-SNT-SALCO? There is a very definite dogleg at SOTEX so AENA have you Northbound on Evens despite being in the other hemisphere until you reach SNT. The corresponding Southbound Odd into the wind is much more direct as SALCO-VES-ESP-BAROK. So there is some method in the madness. BAROK-SNT-SALCO swings and VFA-ARE-ORTAC does not but they are both Northbound and Even.
There are peasant traps. Just be careful at TITOR on UG853 where the sense changes at a prominent dogleg as you transit from ASECNA into Angola, Namibia and South Africa. So always worth a chat with "Haven". They do respond to civilian traffic, and monitor all their frequencies not just the predicted ones. Sometimes it gets awful quiet out there.
Early in my career I was told that Africa starts south of the River Po and finishes overhead Wolseley. Therefore if someone has established Evens Up Odds Down don’t for heavens sake change it. Mind you I suppose we could do it in stages. Light aircraft change over on Mondays, helicopters on Tuesdays, Medium on Wednesdays, Military on Thursdays, Heavy on Fridays…