Not closing balance every month, but every day...if you apply in KL or Laos, you can't allow the balance to go below 500,000 for 3 months in the case of Laos or 6 months in the case of Malaysia.
That $100 fee (roughly 1900 THB) is a tourism tax all foreigners on tourist visas pay when applying for a NZ tourist visa. Exemptions apply for Australian citizens and citizens of certain Pacific Island nations.