I have had a lot of commanders state it is on the weekends for the most part, however I have seen other times. This is not something I believe the developers will release because they want you to check the deals daily =)
Eugenia Misura said:
There is no strict days for such discounts, actually.
It is definitely this coming week.
Unless you guys are going to change it now. Plus whenever Flash goes on a massive rampage capturing Black Sites and downgrading HQs by himself it happens always 2-3 days before a diamond revive discount.
Because he has the help of the developers.