The value pack timer sadly is in real time, so it will count down even when the player is offline. The same applies to all other family buffs, like the Millenial Ginseng, Old Moon Book and Kamasylve Blessing

ALl the timers will count down. If you have got multiple value packs its best to keep them in the storage and activate them as you need them that way you won't burn the time by extending them!