We would like to extend an offer of a new "subscription product" at a discounted rate to both current and non-current (lapsed or never signed up) members. So, here is how we'd like to see it play out: Reduced 6 month membership product for $30 Reduced 1 year membership product for $55 If a current non-member purchases one of these, it's pretty straight forward. For CURRENT members, we would like for the purchase of one of these products to simply ADD the correct time (6 months or 12 months) to the END of their current membership end date (e.g. if they are set to expire in December 2013 and purchase the discounted 12 months, they would be extended to December 2014). Any thoughts on how to do this properly to make sure that membership periods are processed correctly? Thanks in advance!