Get Info (alert) for SLA accounts when creating / editing a ticket

Get Info (alert) for SLA accounts when creating / editing a ticket

Hi,
I tried to program an info / alert, while creating or editing a ticket, when an account has an SLA. Since I couldn't find any relationship to the SLA database, I added a decision field to accounts. A workaround could be if the account also has products (SLA products e.g.), but there's also no relationship to the products database in the workflow aswell.

Further I set up a workflow based on creating and field changing (everytime on modified time) with the criteria of the decision field is true.

Then I made a custom script and related that to the workflow. The custom script looks like this:
info "Account has SLA!";

When creating or editing nothing happens. I even tried specific fields on field changing like priority.  But nothing helps.

Any idea to get a good working solution to notify the user, when an account has a SLA?
Thanks.