JetBlue is increasing bag fees and making the cost more difficult to understand with peak/off peak pricing as well as differences on when you book. You’ll need to navigate to the JetBlue site to see all of the fees, but for flights within US, Latin America, Caribbean and Canada are as follows:
Personally I don’t think you should need a spreadsheet to try and determine how much a bag should cost but I’m not surprised JetBlue is increasing fees as United & American Airlines have also increased fees.