From your dashboard in Ting.com, go to 'Billing History', select a 'Bill - Monthly Usage' and download the .csv files for each category. Upload each file to the respective section below. You can also add Devices and Taxes & Regulatory Fees at the bottom to split as well, click 'Split the Bill!' and your bill will be split!
If you're worried about security and sharing your information in this form, not to worry. The calculations are all done on the browser without saving any data or sending anything across to any servers.
February 2017: A variety of bugs have been fixed in the latest changes. If you were recently getting NaN in the results because either your Messages/Megabytes/Minutes had no usage, that is calculating correctly now. Additional refinements are being done for XL++ plans.
Outside of all of that, I do not use Ting personally frequently enough to have various bill data to thoroughly test the latest changes. Testing will slowly progress to ensure that the calculations are working correctly for all parts of the bill splitting. If you have bills you'd be willing to share that have things like XL+ for Minutes/Messages/Megabytes or international surcharges, I would love to use them for tests. Any personal data will not be shared publicly except to personally validate the app. Please email me!
If any errors do pop up, or if you have any feature requests, you can email to split.ting.app@gmail.com