Device type counts and Raw visit counts in Advan Traffic Data

I noticed that the sum of device counts in DEVICE_TYPE is often greater than the total number of visitors in RAW_VISITOR_COUNTS. As in the first row of the data preview, the raw visit counts is 5, but the Device Type has an entry of {"android":4,"ios":4}", which I interpreted as 4 android devices and 4 iOS devices. How are device types registered to each POI and is the reason the sum of device counts higher than the total number of raw visitors because each visitor can bring multiple devices to the location? Or if a focal visitor makes several trips to the given POI, is it possible that their devices are counted multiple times?

Thank you in advance.