Solved!
In this case, the google performance was actually quite good.
However, it turned out to be the cache refresh setting in the article you pointed out. I was able to find it in the WordPress dashboard under ‘list types’ in the ‘iCal Events List’ settings panel. It was set to 24 hours so I reset it to refresh pretty often. I am doing a web page for some high school music teachers and if there isn’t a pretty quick response they just assume it is not working (even if it is) so I so I set the cache refresh interval pretty low.
They (and I) absolutely love the events list widget and I am in the process of trying out the other features.
Thank you!!