22/52 was the 47,500,000 gil plot.
I know well, because I won that one, lol.
The other two were 50,000,000 because they were deemed to be top-tier/grade and for some reason 22/52 was one tier/grade lower.
I know 30/60 was classed like that because of the baths access.
And I figure 12/42 was classed like that because it's on a main street so it would be a decent venue spot.
22/52, I dunno. It's the highest plot in the ward. You can see everything from there. It was weird to be a couple million cheaper.