But with an International Monetary Fund deal keeping dollar shortage phobias at bay, and the government's comfortable foreign reserve stock, the tax cut may be expected to last at least as long as the IMF calls the shots.
Despite the heavy advertising of vehicles at "new duty rates", "prices slashed," "lowest price in town," many appear to be reluctant to part with fleets imported at higher rates.
A dealer at Bambalapitiya offers a 2006 Toyota Belta (1000cc) at 3.6 million, when his list price for a newer 2007 Toyota Belta (1300cc) car is 3.2 million rupees. Hard to imagine the nutter who will pay 400,000 rupees more for an older and less powerful car.
At Kohuwela, a dealer offers a 2-wheel drive Navara smart cab at 4.2 million rupees. Drive a little further away to Mount Lavinia and the identical Nissan is offered at 4.9 million rupees and the person who buys it must have a place reserved at Angoda.
An ambitious young man advertised his registered 121 Toyota Corolla (2006) at 4.5 million rupees when the better and newer unregistered Toyota Corolla 141 (2007 manufacture) could be had for 3.5 million rupees.The man's explanation for holding out: "The 121 is a better car than the 141." By his logic, the 1984 Toyota DX 72 wagon or the 1972 Corolla KE20 must be worth a fortune.
Then there is the owner of a 2006 Maruti Alto who advertised in a Sinhala language paper asking for 1.35 million for his well maintained car when the same model brand-new car can now be had for 50,000 rupees less.
When the new price was pointed out, the man broke down and said he would never sell his car.
Many rushed to buy the so called "smart cab" because it was imported as a "lorry" and attracted a modest 10 percent duty rate. But with the new duty structure the smart cab is no longer a smart option.
Toyota has slashed the price of 4-wheel drive double cab by more than four million rupees. The 10.5 million rupee 4WD Hiluxe Toyota is now a more attractive six million. Only just over a million more than a smart cab.
The previous duty structure did not encourage the import of diesel-powered dual purpose vehicles.
That is why we have an ageing fleet of vans and double cabs as well as a large number of illegally assembled (erroneously called body-permitted) jeeps.
The new duty will encourage the import of second-hand diesel cabs and vans from Japan as well as South East Asia which should further depress prices. How smart would it be to drive a smart cab then?
With fleets of cars being unloaded at the Colombo port and labourers working overtime to clear space at the harbour to accommodate the flood of vehicles, the market can only slip further with competition getting stiffer.
If you are selling, do it fast. If you want to buy, don't rush.