ticket from Ash to Maidenhead

by Layne
(UK)

When I use the train for work, I usually purchase a ticket from Ash to Maidenhead, but this morning purchased from Ash to Slough.

I don't understand why it was £26.30 for a 6:52 train.

This seems greatly more expensive than the £17.00 for my usual journey at the same time. I understand the journey is a couple of stops further but again, am confused as to why it was almost £10 more.

Layne