Step tracking I-phone 6 PROBLEM

frankiesgirlie

I asked this question before and got no responses, so maybe I didnt ask it correctly. I'll try again. I have my phone on me when I walk the beach for 3 miles each morning and then the rest of the I carry it to add in my remaining daily steps. I also do a 30 minute circuit/Tabata type workout and I don't keep my phone on me during this and add in the calorie burn separately.
My question is if my step tracking says I've burned 300 calories at that point in the day and I go in to log a 200 calorie circuit workout why doesn't the new total burn equal 500 calories?
It's as if the tracking is second guessing me and taking some of the previous burn away and its pis--ng me off to no end.
I think it has to do with negative adjustments but how do I stop it from doing it?
I workout so that I can EAT , besides the heart lung immune system yada yada yada benefits.
Any help would be appreciated.