Wikipedia's article on Crosslink should be right, as I was the one who provided that timetable and calling pattern information.

They may have added Hounslow stops during one of the other timetable periods it ran for (there weren't many), but I'm fairly sure it was only Brentford.
The half hourly Waterloo - Reading via Hounslow semi-fast service was diverted to Weybridge in September 2003 and from the December 2004 timetable called at all stations between Vauxhall and Feltham, where previously it called only at Clapham Junction, Putney, Brentford and Hounslow. This was to afford a decent level of service for stations like Chiswick and Kew Bridge as half hourly is not really good enough. Also bear in mind that although there were four trains per hour between Waterloo and Reading, many of these in the off-peak were formed of only four coaches, whereas now all services are booked for eight coaches.
That said, I'm there's demand for re-introducing a half hourly Waterloo - Reading via Hounslow service throughout the day, calling at principal stations only between Waterloo and Staines, but whether this could actually be pathed is another matter entirely.