In the Historical Earnings Announcement section I have added a bar chart to compare the implied against the actual earnings move (intraday in lighter color, and at day end in stronger color graphically, and for a longer history in a table).
The blue dots represent VIX values, should help to see in one glance how the overall market IV may have influenced the implied move.
The pink numbers represent the remaining life of the options used to calculate the implied move at the time of the earnings announcement (TTM = time to maturity. If the TTM is further out, the implied move (IM) might be inflated).
So in the CCL example, you see in the top table that weekly options started trading in February 2017, which corresponds with the longer TTM values prior to 2017-03 in the chart above.
The pink numbers have caused some confusion, and I agree one needs to get used to it. I tried to add a '?' with tooltips everywhere. But if you still have a better idea please let me know.