how well they have modelled the consumer behaviour as a result of this change.
They did not. TG is effectively a state owned enterprise and not really bound to be profitable (it would be nice but hey...

)
Consumer behavior is definitely not in their decision making. I am very sure that these decisions have been driven purely on a 'math' basis - recalculating costs and hence making the ROP program more profitable - on the assumptions that consumers of course do not react to this.
It's almost like a kid with a lemonade booth selling 10 units a day at a dollar. Kid realizes it needs $20 instead of $10, so just charge $2 instead of $1 - problem solved :-)