I asked the same question and this is Dan’s Reply. If you head to the discussion of the October update, there is a little info about the change and a few responses from Dan.
“Probably the simplest way is to look at the Proofgrade settings. Open a design with a cutline, choose Medium Draftboard, and next to Proofgrade Cut click the arrow. If it says 183 speed, it’s a 45 watt tube. If it says 168, it’s a 40 watt tube.”