Why would 2 schiit aegir amps sound the same as 1?

'but I’m surprised I need to turn my volume dial to roughly the same spot on the dial."

The spot on the volume control is related to gain not power.

Why would 2 schiit aegir amps sound the same as 1?

Because your Klipsch Forte’s are a easy load for the bridged amps, would have been in favour of the stereo amp if the speakers had a harder load yet still efficient.
As a bridged amps looses out in many specification parameters to the same amp in stereo, except in wattage is where they gain. 

Cheers George

The Freya preamp has 12 dB gain available and the Aegir power amp has 22 dB gain available.  Schiit's web site gives no indication that those numbers change when you run in the balanced mode (with 2 Aegirs as monoblocks)  or as a single-ended system (1 Aegir). 

That would indicate that the position of the volume knob would give the same volume output with either setup. So, what you are talking about is having more power available when running the balanced setup. That translates as more headroom (if your listening volume needs more power for peaks) or just a louder possible max volume when running the Aegirs as monoblocks.

You will get what you are looking for by bi amping not bridging. I'm not good at explaining why but here is a link.https://forum.audiogon.com/discussions/bridging-amps-good-idea-or-bad-idea

There is a detailed article and video about this with New Day Record with Ron!

If you have 90db or greater you won't need 2 Aegirs but if you are using 90db or less efficient
you need 2.

Watch the video, he uses Freya Plus+ and Bifrost 2 and 2 Aegirs and blows away everything else in comparison.