I'm only saying to wait a little bit and see how and if the rest of the country follows. I understand your point - the spread appears to be growing, and it looks "unprecedented" at that last moment shown on the graph. When we're dealing with historical data like this and we want to call something current unprecedented, we just want to make sure there isn't a lag in the response, as it were, elsewhere. As I had mentioned earlier, about pricing in this city, a few statistical anomalies have really changed the apparent picture of fuel pricing in this city, but only the apparent picture.
Prices used to move in virtual lockstep. If you saw one station go up before your very eyes, and you wanted to pay the old price, you would have had to find another station in the next few minutes and hope they didn't change before ou got there. After about an hour or so, every station in the city would be exactly the same (aside from a couple independent outliers). At that time, Gasbuddy would always show Regina as having virtually no spread. In fact, the independent outliers would often have the same price on the pump as everyone else, but just have a rebate when you paid. Of course, they would be characterized by Gasbuddy as having exactly the same price as everyone else, based on posted price.
Now, we have a Costco gas station in this end of town, and it's served to lower prices in the city, and also to adjust how quickly they move. The Co-op likes to raise first (and lower last), and price increases happen sooner the further away one is from Costco, and the closest stations to Costco increase their prices last, assuming Costco goes along with the increase. However, once that happens, every station in the city is once again at the exact same price; sometimes, though, the independents don't give rebates, but show a lower price on the sign. Now, though, Gasbuddy calls us the city with the biggest spread in the country. Prices stabilized a couple days ago, and virtually every station has identical pricing, yet we still apparently have the biggest average spread in the country.
Edmonton and Calgary, which are also so characterized with having big spreads, actually do, historically have big spreads, with slightly different prices at every station you pass. That never happens here. The only difference is one station might be on the old price, and one on the new price. That's as far as differences go here.