Measuring Control Area and Command Range

This dispute on how and when can you measure control/command range came up on our recent Sunday meet up. I've looked it up in the rulebook and found the following:-

Measuring Control Area
One don't have measure the caster's full control area when measuring it and estimate how far your model is. The caster can simply measure to any point within his control area i.e. measure how far he/she can advance. This is clearly mentioned in Pg. 75 in Mk II.

Specifically, you can measure the distance from a model to any point within its control area at any time.

Emphasize bolded word.


Measuring Command Range
Measuring command range is apparently very different from measuring control area. The unit leader cannot use it to pre-measure how far it can advance/shoot etc etc. The following is stated in pg. 71 in Mk II.

A unit's controller can measure the distance between the unit commander and a model in its unit anytime during that unit's activation.

Again, emphasize the bolded words .