Schengan Confusion

We went to fetch our passports from the French Embassy today. We were running late and made it in my the skin of our teeth - they close at 12 and we got there at 11:46. :P The lady at the desk gave me a slightly peeved look but you know, I was still in my limits! Anyway, we got the visa and oddly enough I don't look as drugged in this one as in the other two. Something about the light in the picture, although they're all from the same shot. Also, we're a bit confused about how it works. We asked for a multiple entry one, long stay but although the validity is from now until end of March, the duration is listed as 30 days. So we're a bit confused. Hope we haven't spent all that dosh on a dang 30 day visa. That would mean we'd have to do all our trips before the middle of February. :(