Do you have access to Admin WHM cPanel?
I found that setting the following allows updating and saving the tariffs in micromanage mode.
Security center -> ModSecurity Configuration -> Rules Engine secruleEngine -> set Do not process rules
Ask your web host provider to see if "ModSecurity rule 218500 was triggered for your domain". If so, they will whitelist this rule for your domain. If you have more then one domain that you are getting this same error for then your web host provider will need to whitelist these domains.
Now Add ALL of the info below to the top of this file," .htaccess ", found in the root directory:
php_value max_input_vars 3000
php_value suhosin.get.max_vars 3000
php_value suhosin.post.max_vars 3000
php_value suhosin.request.max_vars 3000
The above may solve most of the problems you are having using Jomres Booking System on your server.