Did you try either/or committing the record, and refreshing the window. Short of that, can yo post a sample file?
You appear to have encountered two different problems--a script trigger that is failing to perform a script and a summary field that isn't calculating the value you expect.
Are you using FileMaker Pro or FileMaker Go? I have seen a few reports of trigger issues in Go that were resolved by by restarting the iOS device.
For summary fields, the total that you get depends on:
So you'd need to describe how you attempted to set up your summary field in some detail before we can determine whether there might be some detail not quite right in how you are attempting to use this field.