I think you are missing something if it's not working. What about the min value? You have specified -90, but you are trying to subtract 2000 from the current value of the value.
Quick note: the value operators are actual math types. Setting the operator to - & then setting the number to 2000 doesn't return -2000, it subtracts 2000 from the current number stored in the value & updates it to the new number. If you want to actually set -2000 then use = & change the number to -2000.