Soothsaying for Dummies, Engineering Spec Switching

[Krause]

I was reading on Wowhead that someone recently tested using Soothsaying for Dummies to swap engineering specializations, and then used it to switch back, and upon switching back his previous profession specific schematics that were unlearned became relearned.

Is there any truth to this? Its really not too big an issue because if I'm not mistaken, there are only a handful of non trainer taught spec specific schematics, and I'm pretty sure none are either nodrop or rare. I was under the impression they were gone for good till you relearned them, but it is usually the same copied wiki paragraph posted over and over instead of new user accounts.

[Leinho]

Each time you swap, you relearn everything you already learned before.