Not that big of a deal, as those 2 RP slots should be occupied by closers most of the time. 5 SP slots should give you plenty of room to get in all of your starters on a given day. I can't fathom a scenario in which you would have 6 Starters going on the same day haha. Unless your league uses weekly changes, in that case, it could prove to be a slight advantage.
If you have 5 SP's that start 30 games each, that's 150 games. Depending on how many SP's you are carrying, those extra games from the RP spot could come in handy towards the end of the year. The question is if Smoltz will be around for the end of the year haha. If you are going to try to take advantage of this, I would pitch smoltz in the RP slots early in the year to conserve SP games. That way, you will be able to use those extra starts for other pitchers at the end of the year in case smoltz can't hold up.