Oh I bet it has! The half life of caffeine in your body is relatively short but still significant. If you consume 200mg at 12pm, there's still roughly 50mg left in your body at 10pm, and that's definitely enough on its own to diminish sleep quality. But if you're consuming 5+ cups in the morning that's probably closer to 400mg, so figure you have at least a cup's worth of caffeine left in your body by the time you lay down for sleep at night. This is not linear or universal of course and it's affected by many things including your general metabolic rate, organ health, water consumption, and age, but you get the idea. I wish I didn't ever consume caffeine after 10am but man some days...