PVRTexTool, Is it effective for large amounts of small textures?

Question

I have an iPad app that uses a ton(500+) of small(128x128, 256x256 or less) textures with alpha. At any given time there are probably 30~90 of these textures loaded with around 30 displayed.

The app has slightly slow load times when I use PNG files so i am trying to improve them by using pvr textures.

I want to keep as much quality as possible so there is very little difference between the PNG file and PVR file.

So when I tried converting all of my textures with:

-fOGLPVRTC4 -pvrtciterations8 -pvrtcmedium -yflip0

the file sizes generally increased and the loading times did as well. I know if I use really large textures(1024x1024) then it improves greatly but with small ones it seems not to.

So my question is, is there a way to improve the load times(file size isint much of an issue) even with small textures?

PS. I know that probably creating texture atlases would work but unfortunately I am too far into development to make that kind of change.