added an alternate version that was slower, commented
Minor change that made a minor speed increase
applied same change to slower version: no longer slower
annotated strangeness
added explanatory comments
distributed checks for slight speed increase

But, if we use the two-block (if/else if) version,
   then this change is
   a major speed DECREASE in the 3d test case
switched order: 3% speed increase (why?)
added some assertions to help hunt a bug
Fixed bug, removed assertions.
added explanatory comment
Tweaked when we pass the computed vs. original times

Odd behavior - passing the computed values to the
    children improves 2D, but hurts 3D.
Passing the computed values for the stuff_here checks
    hurts both.
annotated strangeness