I recently made several posts on this very issue, discussing the way things are versus the way they ought to be. Your observations are correct. While the Guide is capable of storing up to 14 days of data, unless you force it to update, it will commonly only keep 7 days available. Because it only keeps 7 days in the Guide, only the next 7 days display in the Scheduled Recordings list.
It is a pain to force the Guide to update by using the FF button in the Guide to skip ahead. And very often when skipping ahead in the Guide, while the Guide info you are viewing is immediately updated, the Guide data that you are not viewing or are skipping past may not be fully updated for several hours/days. This can cause pockets of data containing your Scheduled Recordings to not be updated. So you may have recordings showing as scheduled for days 1-7 and 13-14, but no scheduled recordings listed for days 8-12.