I strongly suspect that Soon just decided he wouldn't inform the Sapphire Guard of where the gate was beyond the coordinates given to him by Girard.

So even though Soon KNOWS the rift is at Windy Canyon, he had no reason to tell the paladins the name of the spot. And since none of the other paladins would dare go check out the gate, he had no reason to question the coordinates period.

But yeah... no clue what the longitude/latitude of my house is so if someone who had cartography skills said "Oh, the longitude/latitude of your house is 33 degrees by 47 degrees" I'd just nod my head and smile.