You can, but It's what the operator feels confident with. Like I would not use something called MPower, many rave about it, but I don't. Great for vomit and urine odour, but anything else it's not for me.
Good psi with good vacs, and the machine does the rest. The key is agitation with the solution on the carpet. No matter what solution I use, I always agitate with my oreck or rotary if on commercial work. Then again if I'm on commercial work, the Dynamall is the product for me :-)