Java Mission Control (JMC) 6.0 does not show hot methods when examining a JFR flight recording
The percentage column is not cpu time, but percentage of the total number of method samples. The same info is displayed as the backdrop in the Count column in JMC 6.0, and I believe if you hover over the column to get the tooltip there might be a percentage number.
I know you are not the first person to miss the percentage column, there is an enhancement request in the JMC Jira for this: https://bugs.openjdk.java.net/browse/JMC-5721