Does MFP "stack" Google Fit's steps and exercise?

reversemigration

I'm curious whether MFP counts Fit's step calories and then considers the other cardio activity recorded separately, or whether the calories expended during exercise are considered over and above the steps that are also involved? For instance, when I go for a 30 minute run, does MFP determine the total number of calories expended, or does it count the steps and the exercise and add them together, thus overestimating them?

I generally don't eat my exercise calories, but I am curious for when I get down to maintenance in the near-ish future. Thanks!