"No alternative route found" error

I bought a TomTom XL 340S on Black Friday at Target for $97. Great price!

I'm happy with it so far.

I updated the application to version 9.022 and the map (US_CANADA_MEXICO) to
version 840.2568 without any problem just to be current.

I thought I'd plan a cross country trip starting from where I live in
southwestern Pennsylvania. I used the "Itinerary planning" function to put
in a bunch of addresses: Denver, Phoenix, Fort Worth, and home. The 340S
planned the route successfully. (Took about 4 minutes, though!) Then I added
another waypoint, "City center" of Ames, IA (my alma mater, ISU, is there).
This generates the error "No alternative route found: S Hazel Ave-Lincoln
Way CO HWY E41, Ames, IA". So I change the waypoint from "City center" to
the intersection of S Maple Ave and E41 CO HWY Lincoln Way (one block
farther east) and it plans the route without error!

I guess I'm a little puzzled as to how this type of error could be occuring
this "late" in the history of GPS software. This is my first GPS so I have
no other machines to compare it to, but I see nothing unique here that
should cause this. If you're curious, try making an itinerary from 1240 York
St, Des Moines, IA (Ankeny) to 2240 York St, Des Moines, IA (Ankeny) with
the intersection of S Hazel Ave and Lincoln Way CO HWY E41, Ames, IA as an
intermediate waypoint and see what you get.

I suppose I can work around these routing problems but should TomTom be made
aware of this problem?

If you did they wouldn't listen. Use it the best way you can but be
prepared for more 'holes' in the future.

That's sad if it's a true error in topology algorithm.

Since I'm a former computer programmer and a mathematician by training the
reason for this error is somewhat intriguing. I seem to have found that the
routing logic will never generate a U-turn at an address or intersection
that you list as a waypoint. In my itinerary the routing has to leave Ames,
IA the same way it came in to generate the fastest path to visit this
waypoint. This means it has to leave the intersection a different way than
it entered it, which is reasonable enough logic. Perhaps the database has
some one-way or no-left-turn attributes at the "faulty" intersection that
give rise to this error. In that case I would not necessarily call this poor
software but a reason to choose another waypoint. Too bad I can't look at
the database this closely, but I'll give TomTom the benefit of the doubt at
this point.

Thanks for your "encouragement" about finding more 'holes' in the future!
(tongue-in-cheek)

Map 840.2568 does not have some streets in my town
Earlier maps do
I believe this map is full of holes