[Mark McLeod]

Think of the shell of the subvi as a single-loop itself.
No output will be released from the subvi until it concludes, just as no new inputs are accepted until it's run again.
It's the same reason that long delays in Teleop.vi are bad.

One way around this is to use a global variable in place of Output and Moving? as a mechanism to pass along intermediate values.
You'd need an additional flag to indicate when it's safe to read those global values, and handle the tiny window where Output has been updated, but Moving? hasn't yet.

Teleop doesn't have this problem, because it writes settings out to the FPGA, rather than producing top-level vi outputs.