Default [Q] HTC Amaze Internal Storage Puzzle

When I use 1 Tap Cleaner, it shows Total 2.46GB, Available 257.18, I have 199 applications and most have been moved to SD card. When I go to storage through my settings, it shows Phone Storage, Total Space is 9.75GB, available space is 6.60GB, Internal Storage: Available space is 257. I used to have more space when I had 330 applications, I am not able to update some apps unless I clear some data on some applications. I clean my cache and data every day. How much space do I have for applications, are there other things besides applications taking my storage, I thought the phone has 16GB storage, plus I have 16G SD card. It is really frustrating experience. Appreciate your responses and help.