Japanese Visa - third degree price discrimination

Usually whenever I travel abroad I need to get a visa and often friends / colleagues from other countries don't need one. I remember once even not being able to make a trip since I was transiting through Canada and didn't have a Canadian visa

When I applied for a Japanese visa though  (yes I still needed one) I was charged $8.00. Interestingly enough the rate that a US citizen has to pay is $28.00.

I guess they know something about third degree price discrimination. I wonder if they obtained the demand curves for these two groups of visitors based on which this came up as the profit maximization price.