[Frozen Lama]

I hate to say "your wrong," but i think you may be a little confused or have just seen some very wonky data. I'm pretty sure that its accepted that you cannot "catch up" to armies with just one army chasing them. those rare times must be when the army is not ordered to move, or when they are ordered to attack your pursuing army. don't know about the multi army thing, but i'm almost positive that chasing armies doesn't work.