How do people score so high in Flip Words 2?

When I looked at the all-time strategy scores in the high score list, I saw that somebody made it up to round 5,397 with a score just over 18,000,000. When I play the strategy mode, though, I can barely make it up to round 50 and my score is between 300,000 and 400,000. That’s with making the biggest words that the grid allows me to make. The submitted words cost one token up until round 20, then starting at round 20, the submitted words cost two tokens. It also goes up one token for every 10 rounds above 20. Is there a trick to this?