Jack Delivery at Lawn Bowls: What I think I see David Corkill Doing

David Corkill is the BBC lawn bowls commentator and a good player himself. On Youtube I was watching him  delivering the jack in the 2016 Scottish Championship and I think I detected something that can benefit ordinary bowlers particularly those who play on grass.

David seemed to be rolling the jack intentionally off the center line.  I believe this action was intentional because he was not having difficulty with line in his regular bowl deliveries. Why was he doing this? There are two possibilities I can think of. (Actually I had already thought of both of these but had never seen anyone else intentionally delivering the jack away from the center.) First, delivering the jack towards the junction of the boundary and the front ditch makes it less likely that you will accidentally ditch the jack, since the path from the center of the mat to the eventual stopping point of the jack will be slightly longer. (It passes across as well as down the rink.) Second, by carefully watching the path of the jack as it moves in this path you can get a better insight for whatever slight sloping may exist. Although this may be very little on the carpet, a player can expect to discover some more significant variations on a grass rink. This jack path would work better for this because delivering the jack off-center more closely approximates the actual curved path of a bowl.

To see the behavior of Corkill view the middle ends of the first set in the following video:

https://www.youtube.com/watch?v=_gZQ6k4L9UU&t=5085s