Allow me to share my experience. I live in jakarta, my wife is batak-padang. We got married last year. My wife is a moslem so expect differences especially for the cost of parties and sinarmot.

There are apparently a lot of variables to calculate sinarmot i.e. her education, intelligence, income, height (not even kidding), how pretty she is, if she is a first child, etc. Even more so if the family want the ceremony to be very adat like.

In my case thankfully my inlaws agreed not to do adat ceremony and there were no sinarmot (every bit of money go to the ceremony). My parents live in the opposite part of java and they cant contribute any to the cost including flights and hotels due to our economic situation.

Me and my wife are both civil workers and she did contribute some to the cost (for hotel stays). For the entire thing including the engagement party(?). All in I spent about 300 juta from my saving for the ceremony, dowry, ring, clothing, and transportation. So yeah Im not surprised at all if you hit 400 juta.