If I have polars to say 20knots, and expedition routes me to an area with wind of 30 knots.....what does it assume my polar to be (does it just use the 20 knot one?  or does  it make some assumption)

In a related way (short hand sailing) if say at 30 knots I stop full on racing mode and so put in polar data that is slower than my 25 knot data,,,,,,what again happens at 35 knots .....does it use the next step down 25.....or assume more...

Thanks,
C