Yep, I'll be paying 350,000 won this month because of that. At least it will only be for one month that we have to pay that amount, although the price of insurance will permanently be more than what it used to be. The number of foreigners have increased so much that the government is starting to charge us more like what Koreans have to pay. I also heard that in the future, your insurance rate may be based more on how much you use it, but nothing set in stone yet. I don't think any of this is just for the Seoul public school workers ( though I could be wrong), but applies to all foreigners in the country.
Anyway, have a nice week~~ :)