What are the rules and procedures for updating a TM-30 upon re-entry into Thailand?

Hello, I have questions about reporting to Thai immigration for update of TM-30 upon re-entry.

Thanks in advance for reading & for any advice.

I'm on a Multiple-Entry Tourist Visa and plan to do a border run this weekend, Chiang Khong/Houayxay. Last time I left the country I was fined 1600 B for not reporting to immigration/updating my TM-30 within 24 hours of reentry--I was 2 weeks late, had no idea about the requirement.

My questions are:

1) Does the fine go up by the day--is it 200 baht/day after the first 24 hours, as I seem to remember reading somewhere?

2) Can I report in Chiang Rai, even though my address is in Chiang Mai?

3) If I report in Chiang Rai, are their reporting hours the same as the CM Immigration TM-30 office (8:30-4:30, every day)? How are the lineups at the Chiang Rai office on a Sunday, if it's open on Sunday?