Tried this now, using B972.10.
1) The LA starts with a 5-knot desired average speed, and alternates sprinting (32 knots) and drifting (4 knots) as expected. Because of the low average desired speed, it spends a lot more time in drift than sprint, which again is expected.
2) You tried to set the average speed by using the textbox between the "Manual Override" and "Sprint and Drift" checkboxes, right? I found a bug that blocked the entered value there from being propagated to the S&D code. Fixed for the next update. As a workaround, the throttle scrollbar can also be used to set the desired average speed value.
(BTW everyone, this is why we need EXACT step-by-step instructions on reproducing issues related to UI. "Feature X doesn't work" is about as useful to us as a condom to a eunuch. We need to know exactly what you did and in what order in order to replicate the problem conditions down to a T. Thanks!)
Sorry to bother you again. Since you said that in case 1 the Los Angeles wasn't sprinting in a noticeable way due to low average mission speed, I tried to change it to "cruise" speed, and once again encountered a bug. The submarine stays at constant 20 kts and instead of sprinting it rotates on itself along its automatic path.
To reproduce: define square area, create patrol ASW mission, spawn any random sub inside the square, assign sub to mission, set "station throttle" to "cruise" in mission settings, select sub, F2, check Sprint and drift. You can change station throttle speed to Full or Flank and it will behave in the same way.