Tvheadend

I am using OpenElec on a NUC and tvh 3.4.37 on an Ubuntu server.

When timeshifting, why can't I rewind back over what I have already watched?

Scenarios
Timeshift is on and paused.
After 10 mins I start watching after 10 mins
I watch for 5 mins and then want to watch the same 5 mins once again.

Or:
Timeshifting a football match and I want to rewind to see the last goal again (and again ...)

Thanks,
Paul