Quoting from the news article
Interior Minister Chaowarat Charnweerakoon said that the PAO Association had urged the ministry to raise their salary from 16,000 Baht to 25,000 Baht and the ministry accepted to consider the proposal.
Meanwhile the Sub-district Administrative Organization or the municipality may also ask for salary raise, [...]
So these officers - not sure if it's only the PAO chairman, or if it's about the officers within the PAO as well - are asking for a raise of 56%, frugal compared with the 100% raise for the headmen. What the article does not say is when they received their last raise, as for the headmen the raise was really overdue with no increase for 10 years.