Originally Posted by JARblue

Sort of right. It's all about the RPMs the engine wants for your current gear/speed. If you stay in neutral long enough to drop below the ideal RPMs for your next gear, then it will rev match if you have SRM on. When downshifting, the RPMs will always be lower than what they should be for the next gear, and the car will always rev match. When upshifting, your RPMs are typically higher than what they will be for the next gear. The caveat you have found is when you stay in neutral too long on an upshift, the RPMs will continue to drop while in neutral and by the time you shift to the next gear the engine needs to rev match. If you have SRM turned off there is no automatic rev matching, and you should be doing the rev matching yourself to minimize wear on the clutch and transmission.