I've t2.micro ec2 instance on AWS using ubuntu OS, also I've attached one elastic ip to that server. I know that t2.micro offers free 750 hours per month for 12 months from creating my account. The problem is that after 1 one week of creating and using t2.micro I've received an alarm for exceeding 85% of free tier package which is 641 hours. I've searched for how aws calculate hours usage and I only found that it if I stopped server it and started it in same hour it will consume 2 hours from free tier. I haven't found anything else.
Anyone can provide more details?