Question about destination_cbgs in Social Distance Data

I’m confused about a variable in Social Distancing Data. According to the description of “destination_cbgs”: Key is a destination census block group and the value is the number of devices with a home in census_block_group that stopped in the given destination census block group for >1 minute during the time period. The destination census block group will also include the origin_census_block_group (so would capture any device that stayed completely at home or were at least seen at some point in the time period within the origin_census_block_group). This means that the difference between the device_count and the count of devices with a destination_cbg that is the same as the origin_census_block_group represents the number of devices that originate from the origin_census_block group but are staying completely outside of it.

If I understand correctly, does this mean that the value only counts in the number of devices with a home in the “key” (census_block_group), and doesn’t count in those devices not living in the “key” (census_block_group) but have stopped in the destination census_block_group? To make my question more understandable, assume there are three census block groups. One person with a home in census block group A goes to census block group B and then goes to census block group C. Another person with a home in census block group B goes to census block group C directly. In this case, for the record with the key as census block group B, should the corresponding value be 1 or 2?