This annoying bug remains unsolved: time calculation is done with 25 KM/h no matter the actual achieved average speed.
Setting of a lower target speed on de course design page has no effect.
I tried the Distance+ IQ but found out it slows down 1030 calculations and operation, also draining the battrery much faster,
I would not recommend to use this IQ, rather exprect a decent fix of this bug.