It's worth pointing out that the only variance it can make under the existing powers is to _raise_ income taxes - this is why it's never been used. Doing so would be political suicide and see a population drain as those able to would quickly move "next door" to an England with lower taxes.

The Barnett formula determines the size of the block grant, not the spending of it. The Scottish Government spends the grant according to its priorities. At the moment these include: free healthcare (including prescriptions), free higher education, and free care for the elderly.