Lactose does add gravity, especially a lb of it. I'd assume you added the lactose after you took your OG reading? It does not ferment at all, but I'd still expect that grain bill to finish out at 1.020 or thereabouts.
In any event, why are you transferring to a secondary at all? Complex stouts can take some time to mature anyway, so I wouldn't really touch it for 3 weeks. I have a breakfast stout going right now (OG 1.074) that I'll just leave for a month and then keg.