Changing default product for pricing in series
When there is a series product, many times you will want the lowest price to display on the lead in to the product display.
To do this you need to set the sort order of the option display for the lowest priced variation. This needs to be done on the children of the series with the product options section of the child series product.
Set the order on the desired default to 0 and make sure all the other options in the series are at least 1.