the prosmatec does not shift gears backwards specially from 2nd to 1st on CNG properly. the advancer of automatic cars is a little different, get that checked. r u also facing the same problem on petrol.
i also have a vti prosmatec on petrol. i have visited murree with no problem. the transmition shift backwards when u floor the accelerator.
i would suggest that u contact logas if u r facing the problem on CNG ony, otherwise go to honda and tell them that the problem is with petrol, the transmition is not shifting properly, ur car is still under warranty, they would do something about it.
also get ur throttle serviced, this improves acceleration and the transmition shifts