MIA arrivals discrepancies

I have noticed that there are discrepancies when it comes to tracking arrivals into Miami international.From 11:30am-2:00pm today I counted 72 arrivals but the wave graph showed the arrivals coming in at 10-12 taking real steep drops while Orlando had 68 or 69 within the same time period and got up to 30+arrivals.Am I missing something on this because I have noticed a pattern?

I just recounted and MIA had 90 arrivals and MCO had 82 during the same time 11:30am=2:00pm.

Since the upgrade on the 17th the problem seems to be fixed now the arrivals are now more in sync than they were before.Great job to the flightaware staff.