Yes, already have start recording 1 minute early, and stop recording 4 minutes late.
I note that when a suggestion is playing the red progress bar on TV commonly shows an exact "30m" or "1hr" which I guess is however long the broadcast slot should be.
I currently have a BBC Timeshift (S14 E4) suggested which shows "1hr". The actual Timeshift programme starts 1m 40s in after start of playing, runs up to the 60 min mark, then ends with the final minute(s) missing.
I doubt it was a 65 minute programme. This is what lead me to believe that the global start / stop recording extensions may not be being applied to suggestions.
If a scheduled program starts late then the end is lost. That doesn't matter if it's a few seconds late as it only truncates the end credits. If it's more it loses part of the programme as well.
That's really annoying for animated comedy (Cleveland Show and similar) where the final seconds deliver the show's punchline.
Looks like we're stuck with how it works; if a suggestion starts late the end may be missing.
I normally do series link suggestions if I find them interesting and deserving of that, but I mostly use suggestions for when I've watched everything I want to watch, there's nothing live, not enough time to fit a DVD in, and I can't be bothered looking through catch-ups :-)
Separate My Show sections for 'definitely want to record' and 'might want to watch when there's nothing else on' as well as 'suggestions' might help but that's an entirely new rabbit hole to go down.