It's possible, yes. Your iPad can be set to not use mobile/cellular data for specific apps, whereas it will always use Wi-Fi, regardless of the origin of that Wi-Fi signal. Similarly, app updates over 150MB won't happen over cell data, but will happily go over Wi-Fi.
So yes, depending upon what you're doing, you can easily use more data on Wi-Fi than on cell without knowing it.
On the Mac using something like TripMode would be potentially helpful for reducing bandwidth usage.