This was all gone over with Aaron Swartz's case though. Normal guidelines for sentencing in U.S. Federal trials is for concurrent sentences for charges stemming from the same crime.

Prosecutors only have 1 trial for each given crime due to the principle of double jeopardy so they have to charge the suspect with everything they think they can prove in case one of the charges gets thrown out on a technicality.

The flip side to that is that typically any conviction(s) on those same charges results in concurrent prison sentences. IANAL so I don't know what types of cases end up in the atypical sequential sentencing but I don't see how this case could possibly end up with sequential sentencing, unless maybe Barrett threatened a cop's family or something like that.