Same workout -- much lower calorie totals

Hi all,

I've had my Watch series 3 for two years, and just got an iPhone 11 Pro to replace my SE about a month ago. It seems like -- suddenly -- the same workout I've done for years is getting me less credit for calories. I do 40 minutes a day on an elliptical trainer. In the recent past, I've gotten credit for usually something like 330 "active calories" and 360 "total calories." (Not sure how there can be a difference during a workout, but that's not my question.) Now, the exact same workout gets me about 240 "active calories" and 300 "total calories." These numbers are way down for the same workout.

Any idea what could be happening here? (Yes, I'm getting more fit, but the change in these numbers happened very quickly.) Suddenly, I'm not meeting my Activity Ring Goal, and that's a bummer.

All ideas or similar experiences would be welcome. Thank you.