This really isn't a guide issue - if you go on the website of the channel and look at their schedule, they will show you the actual start times for each show - history, discovery, and science channels regularly start at 10:02, 10:04, etc.
and the guide I guess can only show 10:00, 10:05, etc. (5 minute intervals)
I adjust my start and endtimes for these channels
Keep in mind I have been a continuous DISH subscriber almost since their begining. Also that History and others have often started shows especially the second or third airing following the first past the top or bottom of the hour. Until the guide provider change I did not miss the begining of those shows. I am now So it isn't the mere fact the shows start past the hour it is the guide provider screwing this and other things up.... and DISH by association. I believe what happened in the past was the timer did not start 5 minutes past as the guide showed then as it does now, but it started on the hour. Whatever the reason I did not have this problem before all these years of watching shows like Pawn Stars and Storage Wars recording on the rerun. (Because my timers were or are full during the first airing) In fact what would happen is I would get the last couple or so minutes of the previous show.
Now that I am aware of the problem I do have it set to record 5 minutes before the start.