Brain cramp - Rule 3

[schwinn]

It's late in the day and I have a few minutes for the rule book and I'm totally confused. I'm thinking I'm just brain dead. Help me sort this out.

3-3-3...A period must be extended by an untimed down if during the last timed down of the period, one of the following occurs:

a. There was a foul, other than USC or nonplayer, or fouls that specify loss of down by either team and the penalty is accepted.

3-3-4...A period shall not be extended by an untimed down if during the last timed down of the period, one of the following occurs:

b. There is a foul that specifies loss of down and the penalty is accepted. The score is cancelled in the event of an accepted foul that specifies loss of down.

Are these two rules in direct conflict, or did I miss a correction from the Fed or am I having a bout of rectal optosis? Please help.