It is now possible to weigh in several times per day and have Garmin Connect - the infrastructure holding the data - both store and present the data. Available from around a week back.
I recently created a free fitnesssyncer account and learned that you could sync Garmin data. It allows multiple weigh-ins to show up from the index scale even though Garmin Connect only shows the most recent for a given day.
Does it auto sync, or you need to subscribe for the sync?