There are probably two aspects to your question to respond to. First is the accumulation of hours for insurability, and Madam Carroll addressed that a little earlier. In 1996, there was a move to an hours-based system, so the contributions are based on the hours of work. If that's in a compressed period, a shorter period worth more hours, then there's no discrimination in the system against working those same amount of hours over a longer period.
On May 30th, 2006. See this statement in context.