The completed Hype Train levels should boost the % of payout to the streamer for subs/gifted subs received during the Hype Train event. There needs to be more reward for the streamer when their audience triggers a Hype Train.

For Example:
Level 1 - No Change in %
Level 2 - Additional 2 %
Level 3 - Increased to 5%
Level 4 - Increased to 8%
Level 5 - Increased to 15%

Perhaps the % increases differently based on the difficulty of the Hype Train the streamer has set up. The harder the levels, the higher the %.