Incremental builds

Hey Netlify Community! I just followed the guide to set up incremental builds with gatsby and netlify: How to scale massive React Static sites with Incremental Builds

Everything builds as it should but when I checked the build time it was the same as before. Here is a link to my apps page Netlify App
Are the builds supposed to be significantly faster with the plugin? If so did I miss something in my configuration? Here is a link to my toml we-roast/netlify.toml at dev · L-Town-FC/we-roast · GitHub

Any thoughts?