It seems we don't know the answer to the question of whether travel through a co-terminal of the
airport of origin counts as travel via the
point of origin and thus violates rule 4(d):
But OP - if you are intending to stopover in Washington and then later stopover in Dallas then you will be in violation of rule 8(2):
2. Maximum two stopovers permitted in the continent of origin of which a maximum of one
stopover is permitted in each direction in the country of origin.