I think the power stroke being inline with the wind up has a very positive effect on accuracy. This is one of my main problems with balearic style as I struggle to convert a more vertical wind up (well, half and half) to a more horizontal power stroke. For ages I always shot high because the sling retained some rising motion from the more vertical wind up. What really killed it was that the amount of rise I got was dependant on the mass of the ammo and the length of the sling, which as you can imagine caused a lot of inconsistency as I moved between different ammo and slings. I think a properly executed balearic throw minimises this effect and mine has improved somewhat towards this too.