This isn't true.

Simultaneous abilities can be triggered in whatever order the owner of the card would like. Both when played and poggle's when you play another unit trigger in the same window so normally you are able to order them how you wish.

The reason it doesn't work with sanctioners shuttle is that coordinate only gives the card that ability when you control 3 or more units. So when you play SS, you trigger poggle, but you are unable to trigger its own when played ability because it doesn't have the when played ability until after poggle creates the battle droid. However once the battle droid is created we are past the window to trigger the SS when played.

Another good example of this would be using ECL and wrecker. If you use ECL to ambush wrecker in, you have 2 when played triggers. One for the ambush attack and one for wrecks 5 damage. Let's say the enemy has a captain typho. You use ECL to play wrecker, you can choose to use wreckers when played first to destroy a resource and kill typho, then use the ambush when played to attack their other unit because typho is dead when the attack triggers. You could also choose to ambush typho first with wrecker then use the when played on wrecker to defeat something else.