The last post is all SM. There are some very small fluctuations in the depression around 0.400, a little more at 0.500, but the port is still quite stable up to 0.550-0.600. Even at 0.600, the depression only climbs about 0.5" but doesn't bounce much. Noise starts building around 0.400-0.500 as well, but it's a consistent noise - no gulping, slurping and bouncing. The TF on the other hand does the gulp, slurp and bounce thing.