With your posted list in A1:A10

Try the TRIMMEAN function
B1: =TRIMMEAN(A1:A10,4/COUNT(A1:A10))

In this section: 4/COUNT(A1:A10)
we're calculating the total percentage of high and low values to exclude.
The function divides that percent equally between high and low values.

With the sample data, the formula returns: 442.5

Does that help?