That should be looked at more seriously. High BP variability is not an encouraging sign. But it could be, and probably is, a matter of how the readings are done. Does she measure herself at home? What type of device? If she measures at home, and aks her to do repeat measurements a minute apart, say, 3 measurements, then we can see whether there is truly some high variability or whether the frog-in-the-sock (that was a new metaphor to me, but one that I can remember) is just an artefact.