This was an old recipe card from a thrift shop. I am assuming that the time and temperature are for a filled pie and you should follow the directions given in the filling recipe for "the remainder of the time"
List of Ingredients
3/4 C shortening
1 T milk
1/4 C boiling water
1 tsp salt
2 C flour
Recipe
Mix the shortening, milk and boiling water to the consistency of whipping cream. Add salt and flour. Mix with a fork until dough cleans sides of the bowl. Roll and bake at 450 degrees for 10-15 minutes then reduce heat to 350 for remaining time.