This solution provides a generic mechanism for defining timers in Indigo.
It's based upon a background task that takes care of decreasing timer values.
All other timer related tasks are done using standard Indigo features like variables and triggers.
That's the brief description. For a full description, including detailed installation and usage instructions, please see the topic.
The script needs to be placed in the Background Task folder of Indigo.
Next a startup trigger has to be defined that starts this script whenever de Indigo Server starts.