Take the prius.
This doc says it is to be taxed at either 160% of FOB value or Rs.4000 per CC whichever is higher. (basis : Hybrid between 1600-2000cc)
The prius has a FOB around JPY 2.44 mil which in LKR terms is 2.44 * 1.34 = LKR 3.3 Mil.
Now
if you use the FOB method your tax should be = 3.3 mil *160% = 5.2 mil (Under old scheme this was 90%)
if you go by CC method your tax should be = LKR 4,000 *1790 = 7.16 mil (Under old scheme this was way less than 4,000, cnt remember the number)
In the previous system the FOB method was higher than CC method for prius.
With this scheme no prices for guessing which is higher and you will now have to pay 7.2 mil as taxes alone instead of the 3.4 mil value that has been charged before. (And this is excluding VAT, i don't know whether that applies or not now)
hope i got it right.