Modifying TCR parameters

If during the lifetime of a TCR app its core parameters are modified, how should this impact to exiting applications or entries?
Should new applications capture a snapshot of the parameters at the time they are submitted?
Otherwise, would those changes apply backwards to applications and challenges going on? I don’t think it would be fair. What if, e.g., the DISPENSATION_PCT parameter changes? Then the challenger may think that it was not worth it.

In the original TCR whitepaper design, a snapshot is taken but at challenge time:

When a challenge is instantiated, a snapshot of the registry’s current canonical parameters are stored with the challenge and a vote begins