Establish a proposed shelflife based on stability data with differenent temperature,

We now are trying to submit the registration dossior for applying a generic chemical drug product. A stability study for under 20℃, 65% for 24 months has been conducted, and obtained a satisfied result. but we now would like to apply a 24 month-shelflife under recommened condition 2℃-8℃ due to commercial reason.
So, that is sound nt so reasonable. how could we do that ?