Boinc shows me estimated time = 2 hours.
But the WU run only 2-3 minutes.

In other projects I can fix this via duration correction factor.
But for milkyway this shows no change and I see this option in the client-state.xml:
<dont_use_dcf/>
Sounds to me that I can not change it?

Yes, if client_state says don't use dcf, then you can't affect the estimated. Only the dev of the science app can change the task generator profile and put in a proper rsc_fpops estimate for the task.

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