[edit4ever]

No worries on the confusion.  The way I built the original process is to save the downloaded data files.  So - let's use the example of March 3rd.  If you are set to download 14 days data at 3am...the system first checks to see if you've already downloaded files for March 3rd at 3am until March 17th at 3am.  Since you have it set for once a day, on March 3rd it downloaded all those files (in 3 hour increments - that's why there are so many files).  Now on March 4th, it runs at 3am and looks for files for March 4th at 3am until March 18th at 3am.  Since you already have the March 3rd through March 17th data downloaded, it only downloads the new March 17th at 3am to March 18th at 3am data (1 day).  That's how it saves bandwidth - by only downloading the new data since the last download.

However - this means that on any given day, your information is 14 days old.  Which has been an issue for some shows.  So the new function, using the example above with the new setting "number of days to delete cache" set for 1 day, on March 4th at 3am, the system check first deletes any cached files for March 4th 3am through March 5th at 3am.  Then it runs as normal, first looking for cached files for March 4th 3am through March 18th at 3am.  Since it doesn't find the files for March 4th 3am through March 5th at 3am and it also doesn't find the files for March 17th at 3am to March 18th at 3am (since that data didn't exist when it ran on March 3rd) - it just downloads those 2 days of data.

I realize this was a bit confusing because of the 3am reference - but I hope it makes sense.

You can also think of it like this.
Starting from a fresh install using the old system with number of download days set to 14: 

On day 1 - it downloads the following days: 1,2,3,4,5,6,7,8,9,10,11,12,13,14
On day 2 - it downloads the following days: 15
On day 3 - it downloads the following days: 16
...
On day 13 - it downloads the following days: 27
On day 14 - it downloads the following days: 28

But the data for 14 is 14 days old (it was downloaded on day 1 and never refreshed. Day 15 data is 13 days old, Day 16 is 12 days old, etc)

With the new system set for with number of download days set to 14 and number of days to delete cache set to 1:
On day 1 - it downloads the following days: 1,2,3,4,5,6,7,8,9,10,11,12,13,14
On day 2 - it downloads the following days: 2,15
On day 3 - it downloads the following days: 3,16
...
On day 13 - it downloads the following days: 13,27
On day 14 - it downloads the following days: 14,28

Now the data your viewing for day 14 is less than 1 day old (it was downloaded on the last run. Day 15 data is still 13 days old, Day 16 is still 12 days old, etc)

Maybe this helped clarify??