Hi,
I think the best will be to use a product custom field so in the backend you will have the possibility to choose between the "2 days" and "one week".
The custom fields fill be display in the product page afterwards and thanks to some view overrides, you will be able to display it in the product listing too.
Custom fields are the best way to add new "options" or data to your products. It is a feature which is include in HikaShop essential and HikaShop Business
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.