(better late than never?)
Oddly I can use two of those on a single pole switch just fine and have in both my basement and garage. My only guess is its down to manufacturing tolerances and I got lucky that the pairs I have don't have too much
resistance when combined.
My issue was with my outside incandescent bulbs for the front of the house which would not work with a non-dimming switch but did work with a dimming switch.