Indeed, at a given slow/mid tempo, say 120 BPM, you will work on resistancy with those 30 bars at ... indeed like Carl said, 4 beats per bar, so one bar has for example that motion:
1 hit - 2 move and prepare - 3 hit - 4 move and prepare
When you increase the tempo, with the same amount of bars it takes less time: 30 bars @ 120 BPM won't last the same time as 150 BPM obviously. So it becomes more of a speed training.
For instance, when I work with music tunes, when I want to focus on speed, I'll play "Tenor Madness" and do my footwork drills for only 12 bars @ 176 BPM ! and in that case indeed we're in the "speed" time lapse. When working on a slower tune, I increase the amount of bars, and work on resistancy.
My picture is more complete now. I couldn't connect it to the actual ball hits. But you are speaking about virtual hits. I can imagine now that you can do these sequences in the precise rhythm, while it plays in your head.
With robot if you set "random" the balls don't come to the same point, so the rhythm is not precise. Maybe it would disturb you as a musician. Also the only definite point there is the hit (1 beat in bar). I'm not sure where exactly I am a the 2nd beat in the bar (in case the 3rd is hit again).
But nevertheless, it's interesting perspective. Almost like you can't do otherwise but hear it.