Storyline 360 : Affectation value to variable

A variable keeps its value until a trigger adjusts it to a new value.

You said the value of your variable isn't changing after the first time. That sounds like something is preventing the subsequent triggers from running. 

For this sort of problem, it's virtually impossible to troubleshoot without seeing the file.

Here are the best practices for uploading a .story file:

• Only include slides that are involved in the problem.
• Be sure all objects, layers, motion paths, and variables have meaningful names.
• If there is proprietary content, replace or delete it. For example, replace proprietary text with ipsum lorem text.
• Be sure to clearly describe the following in the file and/or in the question posted in the discussion (if you haven't already done so):
  • What you want to happen
  • What is not happening that should happen
  • What is happening that shouldn’t happen
  • What you have tried