There are several inconsistencies with whether or not the aliens gain knowledge of their hosts. They seem to be aware of many things that they would have no way of knowing without acquiring their hosts' knowledge (e.g. Reed thinks that T'pol is the most attractive female) but not others (e.g. that the female crewman was female).
In describing the use of a valve to Dr. Phlox, both Captain Archer and Subcommander T'Pol refer to analog clock positions. It is not likely that in the 22nd century members of three different planetary cultures would share common reference to an obsolete Terran technology. They would be far more likely to refer to some shared angular measure, such as degrees.