Serinthia Kelberry

I was finishing up putting a new store together on a parcel of land I bought recentl, and maybe I should have noticed this before, but the amount of memory being reported as "in use" is higher than the sum total of the listed scripts. When I look in About Land, in Script info, the memory in use is around 25MB. That seemed high, so I went down the list of scripts, adding their KB sizes together and came up with about 5.5MB. My avatar was taking up less than 200KB at the time, so there's some memory unaccounted for there.. Is there something I'm missing about how script memory works, or is there a bug when it comes to reporting total usage at the top of the window?