Well, on my 4500, I do have similar offset issues. Live TV is perfect. EPG dead on, and offset is set to "current time".
But for catchup, there is still a few issue.
Example:
Channel "CA: COTTAGE LIFE TV"
According to EPG, earlier today between 10am and 11am, it was playing Holmes on Homes. However either in EPG matrix view, or single channel EPG view, I select "Holmes on homes", it does not play that. If I Go even further back to 3am-4am, it says it should be playing "What on Earth", yet, it actually plays "Holmes on homes". :)
Only reason I chose that, is that Mike Holmes is easy to recognize :)
City TV Montreal and Toronto, even though they show as Catchup, I can't seem to get them working. Live TV is fine. Previous to current program it was playing "2 Broke Girls" and before that "Hudson and Rex", and if I select either one or the other, I don't get an error, but it just stalls.
Anyhow, I don't use it much, so I don't play with it too much, but just saying.
BTW, All times above are Eastern Time.