Yes, you have the general concepts down pat – indicators of relative levels for each of the 16 steps.  If you look up top on the Seq View page, you’ll see MIX – DYNAMICS – OUTPUT ‘big dot’ sliders.

Slide the DYNAMICS away from zero at center, and you’ll see the difference between Rhythm 1 & 6.  That’s your ‘attack & release’ time over each step.

Dynamics is similar to an AD envelope in a synthesizer.  It will determine the ‘width’ of each step.  For example, a Dynamics value of +10 will gate each step to 1/10th of its starting duration at Dynamics=0.

Rhythm 16 is two sets of 8-step ‘fade-ins’.  Automated crescendos.  It’s followed by some fade-out & fade-in combinations.  You can smooth that out with a negative Dynamics value.