Nice app but no family sharing? – MotionX GPS Review

The App Store says it supports Family Sharing for up to 6 people but on my phone it’s free to download but on my sons it asking for $1.99 each. I can understand in app purchases for each user but I thought family sharing for the main app was buy it once for every then in app purchases are per user.
Review by miroperez on MotionX GPS.