Poor fitment, terrible design - Tyrant CNC S&W M&P Shield 2 Round Magazine Extension

I really wanted this work for my M&P Shield 9mm, but Tyrant's design is an epic failure. I assumed the factory magazine "sleeve" (fills the gap between the bottom of the grip and top of the factory base plate) would be unnecessary, so I removed it. Installing the Tyrant mag extension was brain-dead simple, but it does not fill in that huge gap. No big deal. I put the factory sleeve back on the magazine and pushed it into the magwell...and it wouldn't lock into place. I pressed the sleeve tight against the Tyrant mag extension to eliminate any gaps, pushed the magazine into the magwell, and it still wouldn't lock. I oiled the magazine, rechecked the fitment of the Tyrant mag extension and factory sleeve, and tried once again...and still no joy. I finally gave up, put the Tyrant mag extension back in the shipping box and returned it. I bought a Taran Tactical Innovations +2 base pad, which fits perfectly and works flawlessly.