Talon p barrel conversion

So I have a Talon p in 25 caliber mounted in a maddog carbine stock. I recently bought a 177 cal 18 inch barrel from Air Force, and was advised by Tony at Talontunes to use the tank with a standard flow valve to shoot the smaller caliber. I set it up this afternoon with the power wheel on 10 I’m only getting around 700 feet per second with 10.5 grain pellets. I tried putting the original high-flow talon P bottle on. That resulted in Two Shots, the first one was almost 1,200 fps the 2nd shot dumped the tank!!! Both tanks are 13 cu inch.. Can I put the adjustable top hat on the high flow tank and tune to a more normal 850-920 fps for small game and Target shooting.