Website loading much slower now then before instaling your plugin

We were using the free version of Webcraftic Robin image optimization. Our GTMetrix speed load readings were an average 95/100  1.4 second load time our google speed load speed was an average of 65/93.

We bought your premium version because it has Webp. After setup, both GTMetrix and Google load speed are much worse now.

Please help, can you check what the problem is?