On the Android app this appears to be the case - at least for the moment. I cannot speak for Apple.

In the "Settings" we can choose between Gravel, Night-Time, Paved only or Standard surfaces. Depending on the route CT may recalculate the original by selecting one of these.

We may, of course, add a viapoint, drag that to a different location and CT will recalculate.

The website has the option to generate several alternatives to a set destination or even "loop routes" from a set starting point, all showing simultaneously on the screen until one is selected. Of course, the website can be accessed on the browser on our phones.  

Brilliant. Thanks so much. 

Just to say I’ve had a few requests for a more comprehensive planning screen on the app (like the one on the website) so I’m hoping to work on that soon – with the idea that it will give the opportunity to have alternative routes like on the website.

that sounds great Richard.

I was a bit surprised to see that alternative routes is not an option when you have added a via-point. I guess an alternative route for a route with one viapoint would have to be a route that includes the viapoint so that would mean 2 separate calculations, 1 from start to viapoint and 2 from viapoint to end. With only 1 viapoint it would be possible, but with several it would be challenging I guess.

Yep. Essentially the alternative route option is “give me an idea for a via point that will make the journey different”. If you’ve already added via points (let’s call it A-B-C-D-E), then this would mean adding new points between each one, i.e. instantly doubling the number of points. Working out the extra via point is quite computationally challenging so it would probably be both slow and erratic.