I agree it's Not logical that a single base product would perform as well as a combination alternative, but perhaps it's like a car you want to reach a speed of 100mph, you fit a turbo to your car so it does 140mph but the target is 100.....so why bother with the turbo.......... Does that make sense!!!
MS ( I know you hate that term but it's a lot easier to type than its real name ) has other advantages, the biggest is its non-residual nature, if you don't rinse it all out of the carpet when you clean it will not create a problem, (which if you are using a smaller pump can happen) Compare this to one of your favourite chemicals d'lemonene which is incredibly hard to rinse out, I stopped using citrus gel because of how I had to get out my hand tool and get on my knees to rinse it out after using it. If you are using a prespray containing citrus oils (or however they describe it) you need to make sure you give the carpet a really good flushing out so none remains.
You mentioned in the topic on spotting bottles about making a spotter with added d'lemonene which is a really bad idea as it will be impossible to blot out with a cloth.
MS are safer alternative to stronger chemicals, I'm not one for being 'safe' for the sake of it but if you can do the job without risk you might as well
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Richard, I bought it of eBay, can't remember the seller sorry.