Note that there's no I2C bus as such - it's all just bit-banged IOs. 
The Dallas device is a 1-wire bus, not I2C, and I doubt it'll 
interoperate gracefully with I2C, so it's off on its own. 
I think that credible numbers have been extracted from the Dallas 
device, but I'm not sure that the I2C device(s) ave been tested at 
all - however, they're connectd, and can't really be wrong. 

Steve