By my understanding, a transport and the units in it essentially just count as one "thing" during deployment, for purposes of alternate unit placement, determining who goes first, drop count, etc. My question is this: does that scenario differ when units are embarked on a transport that is in reserve? the particular instance I'm curious about is multiple Dark Angels Company Champions embarked on a Drop Pod. Say I have 10 Champions and a Drop Pod. To have all the Champions embarked on the pod and drop them in wherever, do I need to have at least 11 units deployed - 1 for each Champion and one for the pod - or just one? Help!
They only count as one deployment but still count as multiples for the purposes of tactical reserves. 10 Champions and a Drop Pod would be 11 units for the purposes of Tactical Reserves, and you will need at least 11 other units on the battlefield for the deployment to be legal.
"The number of units" and "number of deployments you make" are in no way hard linked, it all depends on how you decide to put units into transports or not.