The rules say if you do not provide the pellets of your choice they will test your rifle with pellets they choose to use to test with. Page 16 of the rule book.
After some more thinking I see what they are trying to do.If you set your rifle up for 14.9gr pellets to be right at 20ft/lb for HV you will be over 20ft/lb if you change to the heavier pellets after your rifle has been tested.