You had a great price there my friend.
If you have let the game roll into a new day the turnip price will be different.
Going back from the afternoon to the morning price will work but once you go to a new day the price is gone for good.
I have one of my towns with 540 bells turnip price so I never open that town unless it is on that date and time.
If anyone needs it I can open the town anytime to turnip sellers.
Just PM me to set up a time.
Started a new town on another cartridge and can make all the bells I need going back and forth selling turnips.
If you can pick up a used AC:NL cartridge and a ds system, its worth it to have that second town's resources available.