Any ideas on this?

Have been watching LHR-CPH for a while, for Friday/Saturday (4th/5th), the availability has got much better within the last few days after having tightened gradually, but do they open up any more seats at shorter notice than this (currently T-72)?

There's an 06:50 on the 5th and an 09:55. The 09:55 has CE Avios availability but the 06:50 has no Avios availability.

So if I book 09:55 I pay £17 + 9,000.
And if I want to change to 06:50 (if it becomes available), I have to pay a futher £8 (£17 paid + £8 change fee = £25), before 09:55 the day before?