Costco is normally a 10 cent spread. Ime, everywhere else has always been 20 cents plus for the spread.
As for comparision to US, when their price goes up 10 cents per gallon, ours goes up 10 cents per litre. Fuel prices are more related to psychology than the price of oil.
Psychologically speaking, gas seems cheap at $1.72 after paying $2.10 but if you roll the clock back........