AB requirement for 1600 NC Mate

Friend is trying to get his 1600 NC mate. He can serve on a 200 ton vessel as a mate or AB. He thinks he has to accept the AB spot because of this requirement:

[B]180 days of service as AB, Boatswain, Quartermaster, or equivalent position on vessels over 100 GRT while holding certification as AB. [/B]

Question is, if he accepts the mate position can he apply this mate sea time towards the 180 AB days?