What? Worked above the threshold for a certain number of weeks? Please post the link for this language or at least a tertiary source discussing the law as it relates to "threshold for a certain number of weeks"
The law clearly states that if you work 30 hours or more per week, that you are a considered full-time and that employers with more than 50 employees must provide health insurance.
The law de-incentivizes the major corporations from employing "full-time" employees. Why would the law not state that 40 hours+ is full-time? At least this way, workers could work 30-39 hours and then purchase their own insurance through exchanges and have extra spending money to boot. Much better than only having 25 hours.