You only share among people with same shared key. So, no, you are not spreading your encrypted file to other people.
At 1:1 it's pretty much direct peer-to-peer transfer. If more nodes are participating, then it can leverage distributed transfers from other nodes that may have part of the whole part of a file.
As they are using BitTorrent technology, perhaps the metadata would contain size of data (number of blocks) to be transferred.
Considering you can choose to NOT use a tracker, and go DHT (or pre-defined host) only, so probably there are some data transfer that are not accounted in this figure.
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You only share among people with same shared key. So, no, you are not spreading your encrypted file to other people. At 1:1 it's pretty much direct peer-to-peer transfer. If more nodes are participating, then it can leverage distributed transfers from other nodes that may have part of the whole part of a file.
As they are using BitTorrent technology, perhaps the metadata would contain size of data (number of blocks) to be transferred. Considering you can choose to NOT use a tracker, and go DHT (or pre-defined host) only, so probably there are some data transfer that are not accounted in this figure.