That's what I do for games I DM. Even roll saves too unless the player has to post anyway.
I am giving VV's method of only using one Initiative roll for each side and resolving results in posted order. Particularly with games that have 5+ players, I think that is the way to go. You can give the players 2-3 days to post as a group, then NPC the ones lagging when you update. I think it will help keep things on track for 2-3 rounds of combat per week, rather than waiting 2-3 days per player.