Share 'Multi Bar Rest Conventions Help Needed!'

I'm preparing a score in Sibelius 7 for a 17 piece Jazz Band. The parts display multiple bar rests where the instrument doesn't play. There are instances where I don't understand what Sibelius has produced. In the attached part, please refer to Rehearsal Mark "B" where it shows a multi-bar rest of 6 measures, followed by two empty bars. Why wasn't this notated as an 8-bar multi-measure rest, as w…