Default [Q] Low Available Storage Space with new Rom

I'm racking my brain trying to figure out what is going on.
after loading a new ROM i have very limited internal storage space left.
Just loaded SOKP rom today and had 1.25gig of space left on a supposedly clean system. Yet if you go the storage tab and add up APPS, Pics -> MISC it only adds up less than 1gig. where is the other 10?
on the bar that color codes the storage space, it looks like 3/4 of it should be available!

i searched and tried these:
http://forum.xda-developers.com/show....php?t=1908711
http://forum.xda-developers.com/show....php?t=2443267

and nothing seems to free up any space.

i noticed this with other ROMS so it is not ROM specific.

Any ideas?
Thanks!

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one thing i found was that spotify's cache took up over 500meg, so i uninstalled spotify then deleted the cached files.
now 2 questions
1) how did it carry over from my previous roms if i wiped and reformatted, etc?
2) how can i find out what other programs / files might be taking up valuable storage space?
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new question: i doubt it's this, but just thought i'd throw it out - i use CWM would using TWRP do anything different? from what i've searched it's just personal prefererance.