Liposuction cost is frequently hard to explain. This is probably because many types of doctors offer liposuction and their costs of doing business are not the same. Liposuction can also be performed in low cost settings (like an office) or higher cost places (like a surgical center.)
The bottom line is that you are value shopping like for anything else. If you choose the cheaper option often you are being operated under numbing alone (more uncomfortable) by the less experienced doctor or by the non-plastic surgeon. Beware that some of the problems with which an inexperienced or poorly trained surgeon may leave you cannot be fixed.