Yes it can work assuming the nodes incentive to capture spokes...

Yes it can work assuming the nodes incentive to capture spokes gives the spokes a cheaper alternative to the present, if not there is friction to scale as there is not benefit of savings

Furthermore, if a spoke (let's call it a franchisee) finds out the node (head office) is getting a nice discount/ kickback as incentive to sell the spokes at a higher cost per transaction than current default, do you think that will end well?

I'll put it another way, do you think the spokes costs' will be lower or higher than their current POS by agreeing to use the Spenda system?

As for the marketing chart, I deal in facts not inhouse assumptions which hold little weight