Nav System Minimum Distance Mode Not Right

[wlb]

My 2001 LS430 Nav system has (like all others) a min time, and a min distance option for calculating the routing.

The min distance option seems to give ridiculous times: It consistently finds lower mileage routes, of course (typically rural roads,,etc), but ALWAYS comes up with less time, often significantly so, vs the min time option.

But these times are WAY too short, and if the time was indeed less, why didnt the min time option find that route?

This inexplicable behavior destroys any confidence in the min distance option.

can anyone explain this behavior, and what if any logic is behind it?

Fyi, all settings appear to be right in the preferences, mpg settings, etc.

Appreciate any comments or explanation.

Thank you

wlbeeton