default range is 22->58, picking up long range increases this by 15m (37->73) which isnt stated on the tooltip, sharpshooter does state this boost but does nothing as you already had it from longrange
it's not only tooltip, falloff bonuss actually doesn't work(same % dmg loss per distance with/without sharpshooter, in both cases falloff starts after default 22m)
he saying that the base range for falloff to start is 22m, with sharpshooter/longrange it should up it like pic below to 37m but even with this the falloff is starting at 22m still, thats a big chunk of damage missing from the falloff adding up over a game