National Highways Authority Of India [NHAI] — Charging same amount for single and return journey

Yesterday I entered a toll located at vaiguntam, Salem, Tamilnadu.. I was charged Rs.65 for entry at 9.27am... And when I return after 2 hours on the same day at 11.16 am again I was charged same amount of Rs. 65 ... Amount detected message for 11.16am journey came on same day stating the charge of 65 rupee... But the amount detected message for 9.27 am journey was received after one day stating the charge of 65rupees ... So in total I was charged 120 rupees for a return journey.. This I way we dint want fasttag system..