confused about boost pressure

[2DaTrakNow]

I am confused about how much boost i am using. My gauge(autometer) shows about 15 sometimes, and others its only 10. Generally when i take off and am under harsh acceleration, my needle goes up to about 15, but then as i start actually going, it comes back down to about 10 and will stay there. For example, if i am in 3rd gear, and i put the pedal all the way down, my boost will build up to about 15 psi. Once the turbo sounds like it is spooled up, and i feel the acceleration, my boost goes back down to about 10 and will stay there until i shift. I was just wondering if this is normal or not? It seems to be running fine and strong.

 

[sadsm]

You probably have a boost leak. Try and do a boost leak test.

 

[16vtawd]

Possibly a boost leak and sometimes T-25s dont hold the same boost to redline