To update your profit margins on specific tasks in bulk, download the pricesheet, make your edits, and reupload the pricesheet.
To begin, navigate to your pricebook. Next to your Member pricing, click on the edit pencil and download the pricesheet.
Once that pricesheet has been downloaded, open the Excel doc. Use the filters at the top to narrow down the category you want, making it easier to update your margins. Anything in gray can be changed, anything in white cannot be changed.
Once you have selected the appropriate category, change Column M. This will update the margin on the individual task. Of course, you can always copy and paste this margin to other cells in Column M to update categories in bulk. Make any other necessary changes to this document.
After the margins have been changed, save the Excel document and re-upload it to the same place it was downloaded: Pricebook --> Member Pricing ---> Upload. Click Save when complete, and the tasks will be updated.