Live graphing comparing manually entered data with existing data

I'm not sure I understand what is going wrong. After clearing the formats that were hiding the values in rows 16, 14, and 4 so I could see those values. Here's what I see:

1) Data entered into Row 16. What do these numbers represent? Time between destinations? Time from start? Time in what units?
2) Row 4 then multiplies the entry in row 16 by 24, suggesting that row 16 is supposed to be entered as time in days. So, the current data suggest that it takes this individual 100 days to go between markers. Seems real slow for a biker, which is why the data for the "ACTUAL" data series is on the bottom of the chart.
3) Row 14 then calculates speed (rate=distance/time) based on the hours computed in row 4 and the distance in row 3.

I would suggest that, rather than a charting problem, something is not right in what you are entering in row 16, and how it is converting that entry to hours. I am not certain what your intention is, but it should be easy once you understand and/or explain what should be entered in row 16 and how that should be converted to elapsed hours in row 4.

The data in line 16 is only there to keep the "#DIV/0!" error from showing. You'll note that the data in line 16 is using "conditional format" to show white text on a white background when the time is that long, because yes, that is unbelievable slow. Once realistic times are entered as the race is underway the entered times would be visible.

The chart that is in my example is not interactive, but a snapshot. I'd like it to update with current average speeds as they are entered.
Time from time station to time station will be entered into line 16, excel will calculate the average speed in MPH and populate line 14.
Line 4 is not visible (white text on white background) and is only used in interim calculations converting [h]:mm to decimal time.

What exactly is not working? It seems to update automatically (for me anyway) as data are entered in row 16. I guess I'm not sure I understand what more you want it to do, or what you want it to do differently.

And the chart does not update for you as you add data to row 16? The chart updates just fine for me on my computer. Have you checked your automatic/manual calculation setting? Though, if that were set to manual, the spreadsheet formulas would not update either.

Does Excel fail to update charts in all spreadsheets, or is it just this spreadsheet that won't update automatically? Anything else in your Excel environment that may be present?

Or am I still not understanding what is going on.

I have never used charts before. (as you might be able to ascertain from my multiple questions. LOL) Are you sure that the chart you see is updating? I don't have anything set in it to update. The line that should display actual speed can be seen sitting hard against the bottom of the graph (robin egg blue). It should rise up to the to match data to the X axis scale. My spreadsheet works fine, it is the line graph that I'm trying to get to give live updates.

You do not need to do anything special to a chart to instruct it to update. Charts should update automatically each time the spreadsheet calculates.

What happens in the spreadsheet and the chart if you enter 3:00 into F16 of your most recent sample?