Hey @Bruce_Lieberthal, welcome to the Community!
It runs like this because Coda is built that way. Automations run on the server side, not in your browser. This is because automations need to run even if nobody has a working PC with the doc opened in a browser. But changes are not saved immediately to the server. To apply the changes, the server has to basically “open” the Coda doc and calculate all of it. Doing that on each change would very quickly overload the server — imagine having to refresh your Coda tab every time you change a cell value. So instead changes are bundled into batches and applied whenever a server becomes free, using a “fair use” scenario . For smaller docs it could be 10-15 seconds as you said, and for larger docs it could be 3-5 minutes.
When you’re testing an automation, it’s run immediately in your browser, not on the server. Keep that in mind btw because certain things that work well during testing won’t work in a real automation run (most notably the User() function)
I totally support the request to have immediate in-browser automation or recalculation rules. Actually here’s my vision for it: