Libertoon, Your info is not quite correct. There are actually 2 different laws you are quoting. 922 is from the "1994 Manufacture Ban". There is also the "1989 Import Ban".
The number of US made parts is dependent upon the rifle, the law requires that there can be a max of 10 imported parts from a specified list, specifically:
a) No person shall assemble a semiautomatic rifle or any shotgun using more than 10 of the imported parts listed in paragraph (c) of this section if the assembled firearm is prohibited from importation under section 925(d)(3) as not being particularly suitable for or readily adaptable to sporting purposes.
(c) For purposes of this section, the term "imported parts" are:
(1) Frames, receivers, receiver castings, forging or stampings
(2) Barrels
(3) Barrel extensions
(4) Mounting blocks (turnings)
(5) Muzzle attachments
(6) Bolts
(7) Bolt carriers
(8) Operating rods
(9) Gas pistons
(10) Trigger housings
(11) Triggers
(12) Hammers
(13) Sears
(14) Disconnectors
(15) Buttstocks
(16) Pistol grips
(17) Forearms, handguards
(18) Magazine bodies
(19) (Magazine) Followers
(20) (Magazine) Floorplates
As an example, the FAL has 17 of these parts (or 16 if you omit the muzzle device). So to be legal, 7 U.S. made parts must be substituted if you include a muzzle brake, or 6 parts without the brake.