While I understand your reasoning, their activity levels still did not come close to what they'd have if wild, therefore not truly burning off the excess seed fats as they should be able to.
Budgies are very well known to be stubborn diet transitioners, more often than not you've got to be more stubborn and crafty

I could talk for hours on Budgie diet, the thing is no one has a clue what's the best. Everyone has STRONG opinions one way or other. I'll always say do your research and pick/modify/throw together a diet that works for YOUR birds and YOU.