There will be costs that will surface sooner. May be they will reflect in accounts in the next quarter :)
But as I said, they are replacing an old-complicated tax system with a new-complicated tax system. Indians are used to living with complicated systems. They will adjust soon. Just hope that the IT backbone does not falter meanwhile
But i reaffirm your point. Implementation is going to be another points of damage to GDP over the next few months.
Hopefully unlikely demonitization, there should be no hidden costs which surface months later.