Because the pricing when creating an instance shows me the cost for the entire month, then works out the average hourly price based on that. This is just creating a GPU VM instance, I don't see how to see the cost of different NVidia GPUs without it.

If you wanted to show hourly pricing, you would show that first, then calculate the monthly price from the hourly rate. I've no idea if the monthly cost includes sustained usage discount and what the hourly cost is for just running it for an hour.