The words have similar meaning, so I can understand why it can get confusing. Here’s the difference in 5 words; you might want to memorize this!
Surrogate: Extension cord
Proxy: Distance
Surrogate testing is only used when the person you’re working on (the subject) is physically present, either touching or within a few feet of you (within the energy field). This type of testing is used when the subject is not testable. You can use self-testing if you’re working on them alone, OR you can plug in another person who is testable. All the muscle testing is done on the surrogate, still on behalf of the subject. The releasing of any emotions is still done on the subject because they are present. Think of surrogate testing like plugging in an extension cord; it’s pretty much the same thing, just with bodies instead of cords.
Proxy testing is used when you want to work on someone who is not physically near you. You can be the proxy yourself if you’re working alone, or you can have someone else become the proxy. All the muscle testing and the releasing of emotions is done on the proxy.