Hi, I'm 100% new to treating my diabetic cat, who just started 1 unit of prozinc twice daily. I understand that we are to administer the insulin every 12 hours, but is there a "buffer?" Like, say I give my cat an injection at 7:00 am . . . I understand I should give her another injection at 7:00 pm, but is 6:45 ok? 7:15? Is one option better than another - 15 minutes too early or 15 minutes too late? How early is TOO early? How late is TOO late?