National Highways Authority Of India [NHAI] — charging central ex-army vehicle

We usually travel from bangalore to chittoor and we have nearly 4-5 toll gates in between.
Every toll gate accept the ex-service man id card and doesn't charge, where as the hoskote toll gate charges 70 rupees, while coming and returning.

70 rupees is not a big deal, but need an explanation that why this happens at one particular toll gate.

While we asked the same question to the authority at the plaza, he replied "government have raised a rule" however it completely out of my understanding that why would government give instructions to one particular plaza to charge ex-service man vehicle.

Expecting an immediate response on this.

Find the plaza pic below.