Sorry John, should have explained - as Dave said - after just agitating the prespray on some jobs it doesn;t look like it needs anything else doing.
That is very often the case - it looks good just after agitating.
this means the pre spray has done its job of breaking down the sticky soiling and the agitation has dispersed it into the carpet over a larger area.
Just waiting for the "washing" now, and as you can imagine if you can get deeper, as with a decent pressure, and suck up more, as with triple vac or Tm, then the cleaner and healthier the carpet will be.
General observations of course.