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.