I am having trouble deploying an App Engine service, and apart from the apparent cause that

So to answer my last question, no this behaviour was not the cause of the inability to deploy - that was caused by the zone exhaustion, and these figures are probably normal.

The zone seemed to have enough resources after 18 hours and an instance automatically started (although I'm still seeing failures on 2nd, 3rd instances so it's still not actually scaling but at least the site isn't entirely down.)