Why does Mission Control show a different GC time to the GC log for a given GC ID?

Question

Mission Control shows:

• GC ID: 301
• GC Duration: 2.595 s

For id 301, the log shows:

[2023-03-02T14:55:45.298+0000][info ][gc,cpu        ] GC(301) User=24.55s Sys=0.85s Real=0.64s

I have 2.59s (which would be 2.595 truncated and not rounded to 2.60) for id=303:

[2023-03-02T14:56:49.677+0000][info ][gc,cpu        ] GC(303) User=37.38s Sys=9.15s Real=2.59s