Samsung Galaxy S5 - S Health cycling app - adds extra 30 minutes ?

[AC Question]

Ever since I have started using S Health Exercise/Cycling app, I have noticed that it adds 30 minutes to the total time as soon as I 'Stop' the exercise. My work is only 4 kms away and takes me 20 minutes but it *always* shows up exactly +30 minutes when I tally it with my watch.

Anyone seen this ?

Bhavesh