Unusual railcard discount

[MikeWh]

While researching another problem I've stumbled upon an odd anomaly with day travelcards and railcards.

Brentwood to zones 1-6 AAA 7-9 off-peak is £16.20. With a railcard that comes down to £10.60.
Cheshunt to zones 1-6 AAA 7-8 off-peak is £16.20, but the railcard price is £10.65. Same with Waltham Cross to zones 1-6 AAA 7.

AFAIK TfL do not sell day travelcards for other than 1-4 (peak only), 1-6 and 1-9. So should the Cheshunt and Waltham Cross versions exist?
I think the correct rounding is actually £10.65 but TfL can't sell tickets ending in 5p from their machine. Is that the reason why the 1-9 is a funny amount?

Any insights into what is going on would be appreciated.

 

[VC00]

Any insights into what is going on would be appreciated.

Most likely due to rounding with fare increase over time? Perhaps an archive of fare data would show this

 

[CyrusWuff]

The correct discounted price should indeed be £10.65, so MTR must be overriding that to match TfL's published discounted price, whereas GA are just using the standard discounts.

 

[MikeWh]

so MTR must be overriding that to match TfL's published discounted price, whereas GA are just using the standard discounts.

The figures come from brfares.com. The tickets I've purchased have been via GA and at TfL's price. I was going to try a Waltham Cross travelcard as that is a GA station, but the absence of zones 8-9 worried me.