Hi Rick and thanks for this.
I've solved the mystery: turns out that selecting Phased Play (i.e. "Manual Defensive Fire") in the Optional Rules Dialog affects the movement rate of units.
I had gotten used to playing JTS games in Phased mode (coming to FWWC via the Napoleonic & Seven Years War games) and so had selected Manual Defensive Fire in the Optional Rules Dialog.
But when I unchecked the Manual Defensive Fire option my units suddenly got their movement rates extended.
Manual Defensive Rules Movement Rate.jpeg (Size: 242.59 KB / Downloads: 6)
Continuous Mode Movement Rate.jpeg (Size: 211.17 KB / Downloads: 6)
Rules--Manual Defensive Fire.jpeg (Size: 41.19 KB / Downloads: 5)
Rules--Continuous Mode.jpeg (Size: 38.28 KB / Downloads: 5)