No. We want to encourage everyone to send out their promos in lossless, so that recipients have the option of downloading in whichever format they like. As such, we have capped the bandwidth usage of a download at that of a 320kbps MP3. So even if a recipient downloads a lossless file from your campaign, you will only incur the amount of bandwidth usage as if they had selected 320 MP3.
This means that sending out a campaign with lossless downloads enabled will never cost you more than sending out a campaign with download quality limited to 320kbps MP3.