No it doesn't - if you have an SL+ set and the same programme is on 3 channels on the same day (SD, HD and +1) - then for:
Record: New only Channel: All It will record just once and by default the HD version
and for: Record: All Channel: All It will record three times - SD, HD and +1!
If the event is on Sky Sports and Channel 4 - then you get both as they are two different programmes per event. In that case it doesn't matter if you use the old or new system - you'll still end up with both versions.
so in your example a 3 hour program I originally to record on CH4 only would now take up 24hours worth of space instead of 3.