All of a sudden I'm being charged (10 Baht) again for withdrawing cash from a Krungsri ATM using a Kasikorn debit card. I like to get 900 Baht four times in a row so I have change. So the 10 Baht adds up.

Check your bank's policy - mine typically allows so many 'other' bank uses per month, then charges after that.   Otherwise, make an effort to use a Kasikorn ATM.  If they don't have an ATM around your area, change to a bank that provides better coverage for you. 

12 minutes ago, joealx said:

I like to get 900 Baht four times in a row so I have change.

"four times in a row", that's the clue to your 10 Baht problem.
You can use other banks ATM for four times per month for free.

(at least for the banks I know)

After that a fee applies.

Been so for years and might become worse in the future (they have plans in the working).

Another common change making drill I've heard of and sometimes do myself, is get 1,000 from the ATM then dip into the nearby 7-11 or Familymart for a small item, walk out with 9xx in "small money".   

 

Again, doesn't seem too convenient to use K-Bank if they don't have ATMs in your normal area.  I use BKK Bank and Krungsi.  BKK has 3 ATMs in my local market area, and one 1 Krungsi ATM.  Also nice if 1 of the BKK ATMs is down/out of money, cross the street and try the others.