I was curious and created my own benchmark - I'm getting quite different results with LV 8.5:
While Loop: Baseline
Floating: ~same
For Loop: 2.5x's faster writing / 4x's faster reading
(I did use a different method with for loops - 0 iterations = read, 1 iteration = write), but testing with nested case structure still was faster than other methods)
Quick check with LV 8.2 shows only 1.2 - 1.3x's performance increase with for loops.