I guess it depends on how many you have now. If you already have a bazillion, adding two might get the red flag for "too many accounts." If you only have a few, it would probably help to add two, as sometimes people get carped at for insufficient revolving TL's.
So for straight scoring, any difference would occur in one of those situations. For most people, it shouldn't have an effect.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit?
FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007