Wilf said:

It' not time! It's the employment in time. if a Soviet MR BN is advancing at 1 kilometre every 90 seconds, then OK, but that rate of advance is VERY rare, and you cannot do it through a minefield or when it costs you 30% of your force per kilometre driven.
I prefer "mobility of fire" to "mobility of shooter". Spike fire is limited to max 8 km. Netfire has triple more. Instead of dragging Spike, sensors by the aveanue of approach are swithching to next. This means that enemy chooses the place of your ambush.