The variations on these kind of things are endless it seems.
I remember a few years back, trawling through a website on English language, I was just as amazed as you were with this, James, to find literally dozens of variations on the old rhyme taught to children about months. There were loads of variations just within the US, let alone in the rest of the world.
For the record, I was taught this version:
30 days hath September
April, June and November
All the rest have 31
Except February alone.
Which has 28 days clear.
And 29 in each Leap Year.
It was fascinating to see all the others though. So many ways to say the same thing.
LabRat