Well that sounds about right craig.
Funnily enough, I did a pretty dirty loop pile today, pale cream (aren't they always). It's pretty cheap stuff the builders put in to new houses, 50/50 wool/polyprop at a guess
The lighting is terrible as I had a big window behind me but you can see the square at the bottom right is yet to be extracted. Looks unimpressive in the photo but absolutely spot on in real life, customer's jaw dropped when she came and looked!

That was using SPM, very quick brush in with a grandi-groomer and then a good stout rinse with the TM at 450psi nice and hot.
I did add some oxidiser to the pre-spray though, as I always do on grubby carpets. So there's two differences but neither should be a deal breaker as long as the rest of the system is spot on.