Is the part building correctly? It appears to have internal ribs in the image with the weight spec, but yours looks to be built solid with top and bottom layers, perhaps filled with infill.
S3D will give you a weight estimate when you PREPARE TO PRINT.
What happens if you set the print up with ZERO top and bottom layers and no infill?
<update> - found information on printing these parts. Your settings are all wrong. Looks like you need to read and follow the instructions.
https://3dlabprint.com/faq/setting-simp ... nt-planes/