If you are talking about your FAN discount, I don't think they will allow those on these plans. Only Military/Veterans of 15%. I have a 25% discount right now, and if I was able to keep that, I would consider changing plans, as it would only be an additional $20 a month and I would not have to worry about the 3 kids using up all the data.
I am on AT&T website now, comparing my plan against the current Unlimited plan. My current bill for 6 smart phones and 1 wearable is 197.50. On the Unlimited Data plan, it's 255 (last weeks rollout). I also get tethering with my plan. So, to move to unlimited, it would be 155 (I pay by CC) + 80 (4 additional smart phones) + 10 (wearable), that would be $235 (only $20 cheaper, but you get tethering). Now, I am a veteran, but not sure who qualifies for the 15% off, as at most, I am looking at maybe another $17.25 off, so I am looking at 227.75, $30 more than I pay now, Even now, I might consider it.