Sorry I was referring to the upside down bulb thing, I've seen it on lots of packaging and commercial/industrial sites. Something about the heat not being able to dissipate properly and frying the base/ballast.
Oh really? Hah. This was a household suspended ceiling fitting with the bulbs pointing up though, which are quite common and puts the base at the bottom, so I can only presume are OK.
Some battery manufacturers say the same thing, I mix batteries too #rocknroll
Seriously if someone can come up with a good reason why two LED bulbs of the same voltage and wattage can't be on the same circuit change my mind...