The elevated readings may very well indicate the detoxing that your mother's body is undergoing, especially with all of the Miracle-Mineral-Supplement she is taking.
Please make sure that she is drinking a LOT of water. She should be drinking at least a liter of water for every 40lbs of body weight per day.
Also, try to shift her diet to a more alkaline or "green" one, based upon organic fruits and vegetables. There is a suggestion below about Dr. Gabriel Cousens, and his diet is awesome; another great example of an alkaline diet is from Dr. Robert Young.
Use a blender, and make organic, "green" smoothies ... you can make these delicious by adding a fresh grapefruit. Drinking these a couple of times per day will give the body a tremendous boost from the enzymes, coupled with vitamins and anti-oxidants.
If the Miracle-Mineral-Supplement load is too high for your mother under the regimen you are following, then reduce the drops and/or the frequency, but do not discontinue. Adjusting the dosage but maintaing a continuous Miracle-Mineral-Supplement intake will assure that her body continues to cleanse without setting her back.