Bloody glow!!

Has anyone else found that when they record a late period, glow completely moves your cycle around? I'm so annoyed that I've only just noticed! I thought I was 13dpo but I'm actually 17! I've had to sit and work it all out. I only noticed when I saw that my ovulation days had changed on my month view! Luckily I had recorded when we had sex this month which was every ovulation day but now my month view says we had sex everyday a week later on my revised ovulation week! Has anyone else had this happen?