Weird thing - Hangouts on AT&T eats up far more data than Hangouts on Sprint

So here's something weird - I had been using hangouts on FreedomPop's Sprint service and it didn't use up much data. I recently started using FreedomPop's AT&T sim, and noticed that hangouts is eating up a lot more data. How is this even possible? Been using Opera Max on the FP-Sprint phone and on the FP-AT&T phone to conserve data and almost everything except hangouts is blocked on both phones, so what gives? Any ideas?

That's interesting.

I'll try that on my devices and see if there's a difference.

Better data speed, higher data use?
Same thing happens when you compare idle data use on 3G vs LTE.

How are you metering the data to make the comparison?

No metering, just seeing how much data is used throughout the day. When apps detect wide open lane, they take advantage of it.

I noticed that on my work iPhone 6S on ATT (not FP), it uses way less data for the same apps & similar usage than on Android on either R+ or FP LTE SIM on ATT. I know this anecdotal point sorta (but not entirely) contradicts your post, but it's been my experience for over 1 year on R+, & the few months I've had on FP LTE on ATT.

So, in my experience, iOS ATT uses less data than Android (from Ice Cream Sandwich to Nougat) Sprint MVNO & ATT MVNO. Not sure that makes sense.