“Also , it only allows one programme per DVD in HS mode. So if you want to put more than one programme on a DVD in SP, LP, FR modes then you can. In HS mode , you can’t!”
This is very strange, maybe it’s this way for your model. For the EH50s and EH75VS, you can definitely high speed multiple programs and customized chapters are maintained. The only constraint is you must be within the 4409 MB limit for 4.7GB disc (~ 2 hours, 10 minutes of programming originally recorded at SP quality). You can actually fit more programs if you use high-speed burn.
The drawback for using high-speed is that you lose the original aspect ratio if the program was originally recorded in widescreen. To keep it widescreen, you must burn at real time by selecting SP, LP, etc. If you choose H-S, it’s much faster but the program is re-encoded (right term?) back to full screen.
But I’m still using a full screen TV, so it doesn’t matter to me.