Purchased a new key for 2017 for merging...

cerebrave

Hi,

I just purchased a new key recently (Total security - 5 devices) as part of the new year discount.  Additionally I do have currently running activated subscription with 234 days remaining (Total security (TS) - 3 devices) - purchased as TS2016 and upgraded to TS2017.  Now, I'm thinking of two options:

1. Input my new key to my bit defender central - in my hope to merge and extend my existing TS subscription to 599 days - but I'm worry that the 3 and 5 devices differences hinders the merging.

2. Keep my key, and insert them just when my current subscription is about to end, to avoid significant overlap subscription, but worry if my newly purchased key may expire somehow..

Can anyone suggest me with a solution?  My intention is to extend my subscription, but afraid of losing the days I would like to extend.

Thanks!