flyingphil1
The stalling angle of attack is the stalling angle of attack. The speed at which it is reached depends upon the weight/load factor; I would suggest that you have either mis-quoted the manual or that it is wrong/misleading.
I would also be wary of assuming that just because a stall warner has sounded at a higher IAS than you would expect that it is incorrectly set. Pitot-static errors are covered in most training manuals and may go some way to explaining your example.